Heat wave: Difference between revisions

Latest revision as of 02:16, 18 December 2025

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File:Heat Wave.jpg

A high pressure system in the upper atmosphere traps heat near the ground, forming a heat wave (for North America in this example)

File:Heatwave in London (9217).jpg

Scorched grass in Greenwich Park, London, England, during a heatwave in August 2022.

A heat wave or heatwave, sometimes described as extreme heat, is a period of abnormally hot weather ^[1]Template:Rp that lasts for multiple days. A heat wave is usually measured relative to the usual climate in the area and to normal temperatures for the season.^[2] The main difficulties with this broad definition emerge when one must quantify what the 'normal' temperature state is, and what the spatial extent of the event may or must be. Temperatures that humans from a hotter climate consider normal can be regarded as a heat wave in a cooler area. This would be the case if the warm temperatures are outside the normal climate pattern for that area. Heat waves have become more frequent, and more intense over land, across almost every area on Earth since the 1950s, the increase in frequency and duration being caused by climate change. According to the World Meteorological Organization, heat waves continued to intensify in 2024, with record-breaking temperatures reported in Europe, North America, and China. Many regions experienced consecutive days above 45°C, highlighting the increasing frequency and severity of extreme heat events worldwide.^[3].

Heat waves form when a high-pressure area in the upper atmosphere strengthens and remains over a region for several days up to several weeks.^[4] This traps heat near the earth's surface. It is usually possible to forecast heat waves, thus allowing the authorities to issue a warning in advance.

Heat waves have an impact on the economy. They can reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure.^[5]^[6] Severe heat waves have caused catastrophic crop failures and thousands of deaths from hyperthermia. They have increased the risk of wildfires in areas with drought. They can lead to widespread electricity outages because more air conditioning is used. A heat wave counts as extreme weather. It poses a danger to human health, because heat and sunlight overwhelm the thermoregulation in humans.

Definitions

Template:Sidebar with collapsible lists There are several definitions of heat waves:

The IPCC defines a heatwave as "a period of abnormally hot weather, often defined with reference to a relative temperature threshold, lasting from two days to months."^[7]^[1]Template:Rp
A definition based on the Heat Wave Duration Index is that a heat wave occurs when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by Script error: No such module "convert"., the normal period being 1961–1990.^[8] The same definition is used by the World Meteorological Organization.^[9]
A definition from the Glossary of Meteorology is:^[10] "A period of abnormally and uncomfortably hot and usually humid weather."
Marine heatwaves are generally described as prolonged discrete periods of unusually warm sea surface temperatures in a specific region. At this time the most commonly accepted definition is that proposed by Hobday et. al.^[11] which refers to an algorithm that uses percentile values for temperatures, and defines a threshold set as the 90th percentile for a given day of the year, above which one can say a marine heatwave is occurring. This definition can be used with temperature data acquired anywhere in the world, allowing for comparisons across different observations and latitudes.

Definitions by country

Europe

Denmark defines a national heat wave (hedebølge) as a period of at least 3 consecutive days in which the average maximum temperature across more than half the country exceeds Script error: No such module "convert".. The Danish Meteorological Institute also has a definition for a "warmth wave" (varmebølge). It defines this using the same criteria for a Script error: No such module "convert". temperature.^[12] Sweden defines a heat wave as at least five days in a row with a daily high exceeding Script error: No such module "convert"..^[13]

In Greece, the Hellenic National Meteorological Service defines a heat wave as occurring over three consecutive days with temperatures at 39 °C (102 °F) or higher. In the same period the minimum temperature is Script error: No such module "convert". or more. During this period, there are either no winds or only weak winds. These conditions occur in a broad area.Script error: No such module "Unsubst".

The Netherlands defines a heat wave as a period of at least five consecutive days in which the maximum temperature in De Bilt exceeds Script error: No such module "convert".. During this period the maximum temperature in De Bilt must exceed Script error: No such module "convert". for at least three days. Belgium also uses this definition of a heat wave with Ukkel as a reference point. So does Luxembourg.

In the United Kingdom, the Met Office operates a Heat Health Watch system. This places each Local Authority region into one of four levels. Heat wave conditions occur when the maximum daytime temperature and minimum nighttime temperature rise above the threshold for a particular region. The length of time above that threshold determines the level. Level 1 represents normal summer conditions. Level 2 occurs when there is a 60% or higher risk that the temperature will be above the threshold levels for two days and the intervening night. Level 3 arises when the temperature has been above the threshold for the preceding day and night, and there is a 90% or higher chance that it will stay above the threshold in the following day. Level 4 is triggered if conditions are more severe than those of the preceding three levels. Each of the first three levels gives rise to a particular state of readiness and response by the social and health services. Level 4 involves a more widespread response.^[14] The threshold for a heat wave occurs when there are at least three days above Script error: No such module "convert". across much of the country. Greater London has a threshold of Script error: No such module "convert"..^[15]

In Ireland, a heat wave is defined as temperatures exceeding Script error: No such module "convert". for five or more consecutive days.^[16]

North America

In the United States, definitions also vary by region. They usually involve a period of at least two or more days of excessively hot weather.^[17] In the Northeast, a heat wave is typically when the temperature reaches or exceeds Script error: No such module "convert". for three or more consecutive days. This is not always the case. This is because the high temperature ties in with humidity levels to determine a heat index threshold.^[18] The same does not apply to drier climates. A heat storm is a Californian term for an extended heat wave. Heat storms occur when the temperature reaches Script error: No such module "convert". for three or more consecutive days over a wide area (tens of thousands of square miles).^[19] The National Weather Service issues heat advisories and excessive heat warnings when it expects unusual periods of hot weather.

In Canada, heat waves are defined using the daily maximum and minimum temperatures, and in most of the country, the humidex as well, exceeding a regional threshold for two or more days. The threshold in which daily maximum temperatures must exceed ranges between Script error: No such module "convert". in Newfoundland and Script error: No such module "convert". in interior British Columbia, though this threshold is much lower in Nunavut, ranging between Script error: No such module "convert". and Script error: No such module "convert"..^[20]

Oceania

In Adelaide, South Australia, a heat wave is five consecutive days at or above Script error: No such module "convert"., or three consecutive days at or over Script error: No such module "convert"..^[21] The Australian Bureau of Meteorology defines a heat wave as three or more days of unusual maximum and minimum temperatures.^[22] Before this new Pilot Heatwave Forecast there was no national definition for heat waves or measures of heat wave severity.^[22]

In New Zealand, heat waves thresholds depend on local climatology, with the temperature threshold ranging between Script error: No such module "convert". in Greymouth and Script error: No such module "convert". in Gisborne.^[23]

Marine Heatwaves

Script error: No such module "Labelled list hatnote". Marine heatwaves have become a prominent subject of research in recent years, reflecting the fact that since the turn of this century many ocean areas have experienced peaks of temperatures, along with more frequent, more intense, and more prolonged warming events than ever met on record.^[24] The genesis of marine heatwaves is mainly driven by a combination of oceanic and atmospheric factors, often triggered by high pressure systems that will reduce cloud cover and increase solar absorption by the sea surface. Human-induced climate change appears bound to play a growing role in the development of marine heatwaves, with increasing impacts on marine ecosystems, such as mass mortality in benthic communities, coral bleaching events, disruptions in fishery catches, and shifts in species distributions.

Observations

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File:Map of increasing heatwave trends over the midlatitudes and Europe.webp

Map of increasing heat wave trends (frequency and cumulative intensity) over the midlatitudes and Europe, July–August 1979–2020^[25]

It is possible to compare heat waves in different regions of the world with different climates thanks to a general indicator that appeared in 2015.^[26] With these indicators, experts estimated heat waves at the global scale from 1901 to 2010. They found a substantial and sharp increase in the number of affected areas in the last two decades.^[27]

One study in 2021 investigated 13,115 cities. It found that extreme heat exposure of a wet bulb globe temperature above 30 Celsius tripled between 1983 and 2016, and if the effect of population growth (increasing the urban heat island effect) during those years is excluded, the exposure increased a further 50%. The researchers compiled a comprehensive list of past urban extreme heat events.^[28]^[29]

Causes

Heat waves form when a high pressure area at an altitude of Script error: No such module "convert". strengthens and remains over a region for several days and up to several weeks.^[4] This is common in summer in both the Northern and Southern Hemispheres. This is because the jet stream 'follows the sun'. The high pressure area is on the equator side of the jet stream in the upper layers of the atmosphere.

Weather patterns are generally slower to change in summer than in winter. So, this upper level high pressure also moves slowly. Under high pressure, the air sinks toward the surface. It warms and dries adiabatically. This inhibits convection and prevents the formation of clouds. A reduction of clouds increases the shortwave radiation reaching the surface. A low pressure area at the surface leads to surface wind from lower latitudes that brings warm air, enhancing the warming. The surface winds could also blow from the hot continental interior towards the coastal zone. This would lead to heat waves on the coast. They could also blow from high towards low elevations. This enhances the subsidence or sinking of the air and therefore the adiabatic warming.^[30]^[31]

In the eastern regions of the United States a heat wave can occur when a high pressure system originating in the Gulf of Mexico becomes stationary just off the Atlantic Seaboard. Hot humid air masses form over the Gulf of Mexico and the Caribbean Sea. At the same time hot dry air masses form over the desert Southwest and northern Mexico. The southwest winds on the back side of the high continue to pump hot, humid Gulf air northeastwards. This results in a spell of hot and humid weather for much of the eastern United States and into southeastern Canada.^[32]

In the Western Cape Province of South Africa, a heat wave can occur when the low-pressure area offshore and the high-pressure area inland combine to form a bergwind. The air warms as it descends from the Karoo interior. The temperature will rise about 10 Celsius from the interior to the coast. Humidity is usually very low. The temperature can be over 40 Celsius in summer. The highest temperature recorded in South Africa (51.5 Celsius) occurred one summer during a berg wind along the Eastern Cape coastline.^[33]^[34]

The level of soil moisture can intensify heat waves in Europe.^[35]^[36] Low soil moisture leads to a number of complex feedback mechanisms. These in turn can result in increased surface temperatures. One of the main mechanisms is reduced evaporative cooling of the atmosphere.^[35] When water evaporates, it consumes energy and therefore lowers the surrounding temperature. If the soil is very dry, then incoming radiation from the sun will warm the air. But there will be little or no cooling effect from moisture evaporating from the soil.

Climate change

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Impacts on human health

File:Heat stroke treatment, Baton Rouge, 2016 Louisiana floods.jpg

Heat stroke treatment at Baton Rouge during the 2016 Louisiana floods

Heat-related health effects for vulnerable humans

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Mortality

File:NWS HeatRisk Categories.jpg

The National Weather Service risk categories for NWS HeatRisk

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Underreporting of fatalities

The number of heat fatalities is probably highly underreported. This is due to a lack of reports and to misreporting.^[37] When considering heat-related illnesses as well, actual death tolls from extreme heat may be six times higher than official figures. This is based on studies of California^[38] and Japan.^[39]

Part of the mortality during a heat wave may be due to short-term forward mortality displacement. In some heat waves there is a decrease in overall mortality in the weeks after a heat wave. These compensatory reductions in mortality suggest that heat affects people who would have died anyway, and brings their deaths forward.^[40]

Social institutions and structures influence the effects of risks. This factor can also help explain the underreporting of heat waves as a health risk. The deadly French heat wave in 2003 showed that heat wave dangers result from a combination of natural and social factors.^[41] Social invisibility is one such factor. Heat-related deaths can occur indoors, for instance among elderly people living alone. In these cases it can be challenging to assign heat as a contributing factor.^[42]

Heat index for temperature and relative humidity

Template:HeatTable The heat index in the table above is a measure of how hot it feels when relative humidity is factored with the actual air temperature.

Psychological and sociological effects

Excessive heat causes psychological stress as well as physical stress. This can affect performance. It may also lead to an increase in violent crime.^[43] High temperatures are associated with increased conflict between individuals and at the social level. In every society, crime rates go up when temperatures go up. This is particularly the case with violent crimes such as assault, murder and rape. In politically unstable countries, high temperatures can exacerbate factors that lead to civil war.^[44]

High temperatures also have a significant effect on income. A study of countries in the United States found that the economic productivity of individual days declines by about 1.7 percent for each degree Celsius above Script error: No such module "convert"..^[45]

Surface ozone (air pollution)

Script error: No such module "labelled list hatnote".High temperatures also make the effects of ozone pollution in urban areas worse. This raises heat-related mortality during heat waves.^[46] During heat waves in urban areas, ground level ozone pollution can be 20 percent higher than usual.^[47]

One study looked at fine particle concentrations and ozone concentrations from 1860 to 2000. It found that the global population-weighted fine particle concentrations increased by 5 percent due to climate change. Near-surface ozone concentrations rose by 2 percent.^[48]

An investigation to assess the joint mortality effects of ozone and heat during the European heat waves in 2003 concluded that these appear to be additive.^[49]

Impacts on societies

Reduced economic outputs

File:09 Aus heatwave map.PNG

2009 southeastern Australia heat wave, thermal map approximate affected area shown in red

Calculations from 2022 suggest that heat waves will shrink the global economy by about 1 percent decrease by the middle of the 21st century.^[50]^[51]^[6]

Heat waves often have complex effects on economies. They reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure that is not suitable for extreme heat.^[5]^[6] In 2016, a marine heatwave in Chile and its subsequent harmful algal bloom caused $800 million (USD) in export losses for the aquaculture industry as salmon and shellfish died off.^[52]

Reduced agricultural outputs

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Heat waves are a big threat to agricultural production. In 2019 heat waves in the Mulanje region of Malawi involved temperatures as high as Template:Cvt. This and a late rain season scorched tea leaves and reduced yields.^[53]

Farmed animals

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Infrastructural damage

Heat waves cause roads and highways to buckle and melt,^[54] water lines to burst, and power transformers to detonate, causing fires. A heat wave can also damage railways, by buckling and kinking rails. This can slow down or delay traffic. It can even lead to cancellations of service when rails are too dangerous to traverse by trains.

Power outages

Heat waves often lead to spikes in electricity demand because there is more use of air conditioning. This can create power outages, making the problem worse. During the 2006 North American heat wave, thousands of homes and businesses went without power, especially in California. In Los Angeles, electrical transformers failed, leaving thousands without power for as long as five days.^[55] The early 2009 southeastern Australia heat wave caused major power disruptions in the city of Melbourne. They left over half a million people without power as the heat wave blew transformers and overloaded a power grid.

Impacts on the environment

Wildfires

A heat wave occurring during a drought can contribute to bushfires and wildfires. This is because a drought dries out vegetation, so it is more likely to catch fire. During the disastrous heat wave that struck Europe in 2003, fires raged through Portugal. They destroyed over Script error: No such module "convert". of forest and Script error: No such module "convert". of agricultural land. They caused about €1 billion worth of damage.^[56] High end farmlands have irrigation systems to back up crops.

Floods

Heat waves can also contribute to flooding. Because hot air is able to carry more moisture, heatwaves may be followed by extreme rainfall especially in mid-latitude regions.^[57] For example, the record-breaking heat wave that afflicted Pakistan beginning in May 2022 led to glacier melt and moisture flow. These were factors in the devastating floods that began in June and claimed over 1,100 lives.^[58]

Wild animals on land

Researchers have predicted that roughly 10-40% of all land vertebrate species will be affected by heat waves by 2099, depending on the amount of future greenhouse gas emissions.^[59] Heatwaves present an additional form of stress and evolutionary pressure for species that already deal with habitat loss and climate change.

Species have a thermal range of tolerance that describes the temperatures where they perform best. Temperature conditions that are outside of this range may experience decreased fitness and the inability to reproduce.^[60]^[61] The species with sufficient genetic variation will be able to ensure some individuals can survive frequent days of high temperatures in the future.^[62]

Oceans

Marine heatwaves may cause mass mortality in fish populations, especially for species that are better adapted to cooler temperatures.^[63] Species that have adapted to warmer temperatures may expand their range during a heatwave. These invasive species may outcompete the native species that experience higher mortality during a heatwave, which disrupts ecosystem functioning.^[63] Marine heatwaves have also been correlated with negative impacts on foundation species such as coral and kelp.^[64]

Options for reducing impacts on humans

A possible public health measure during heat waves is to set up air-conditioned public cooling centres. Adding air conditioning in schools provides a cooler work place.^[65] But it can result in additional greenhouse gas emissions unless solar energy is used.

Policymakers, funders and researchers have created the Extreme Heat Resilience Alliance coalition under the Atlantic Council. This advocates for naming heat waves, measuring them, and ranking them to build better awareness of their impacts.^[66]^[67]

Recent examples by country or region

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China

A study found the average resident in China was exposed to 16 days of heat waves in 2023, with more than 37,000 heat wave-related deaths. Besides, the number of work hours lost due to heat stress in China was 36.9 billion in 2023, and China's citizens experienced a 60% surge in lost safe outdoor activity hours, with each person losing 2.2 hours on average each day. The study predicted that by the 2060s, annual heat wave-related mortality is expected to reach 29,000 to 38,000 in China, with a 28% to 37% increase in work hours lost.^[68]

United States

Script error: No such module "Multiple image". In July 2019, there were over 50 million people in the United States in jurisdictions with heat advisories. Scientists predicted that many records for highest low temperatures would be broken in the days following these warnings. This means the lowest temperature in a 24-hour period will be higher than any low temperature measured before.^[69]

According to a 2022 study, 107 million people in the US will experience extremely dangerous heat in the year 2053.^[70]

Heat waves are the most lethal type of weather phenomenon in the United States. Between 1992 and 2001, deaths from excessive heat in the United States numbered 2,190, compared with 880 deaths from floods and 150 from tropical cyclones.^[71] About 400 deaths a year on average are directly due to heat in the United States.^[37] The 1995 Chicago heat wave, one of the worst in US history, led to approximately 739 heat-related deaths over 5 days.^[72] In the United States, the loss of human life in hot spells in summer exceeds that caused by all other weather events. These include lightning, rain, floods, hurricanes, and tornadoes.^[73]^[74]

About 6,200 Americans need hospital treatment each summer, according to data from 2008. This is due to excessive heat, and those at highest risk are poor, uninsured or elderly.^[75]

The relationship between extreme temperature and mortality in the United States varies by location. Heat is more likely to increase the risk of death in cities in the northern part of the country than in southern regions. As a whole, people in the United States appear to be adapting to hotter temperatures further north each decade. This might be due to better infrastructure, more modern building design and better public awareness.^[76]

References

↑ ^a ^b IPCC, 2022: Annex II: Glossary [Möller, V., R. van Diemen, J.B.R. Matthews, C. Méndez, S. Semenov, J.S. Fuglestvedt, A. Reisinger (eds.)]. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, pp. 2897–2930, Script error: No such module "CS1 identifiers"..
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↑ Dead Heat: Why don't Americans sweat over heat-wave deaths? By Eric Klinenberg. Slate.com. Posted Tuesday, 30 July 2002
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Template:List of heat waves

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[:42-1] IPCC, 2022: Annex II: Glossary [Möller, V., R. van Diemen, J.B.R. Matthews, C. Méndez, S. Semenov, J.S. Fuglestvedt, A. Reisinger (eds.)]. In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, pp. 2897–2930, Script error: No such module "CS1 identifiers"..

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[72] Near-Fatal Heat Stroke during the 1995 Heat Wave in Chicago. Annals of Internal Medicine Vol. 129 Issue 3

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[slate-74] Dead Heat: Why don't Americans sweat over heat-wave deaths? By Eric Klinenberg. Slate.com. Posted Tuesday, 30 July 2002

[75] Most People Struck Down by Summer Heat Are Poor Newswise, Retrieved on 9 July 2008.

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@@ Line 1: / Line 1: @@
 {{Short description|Prolonged period of excessively hot weather}}
-{{Distinguish|heat burst}}
+{{Distinguish|Heat stroke|Heat burst}}
-{{For|the disease that is produced by heat|Heat stroke}}
+{{For-multi|the Glass Animals song|Heat Waves|other uses|Heat wave (disambiguation)}}
-{{Redirect|Heat waves|the Glass Animals song|Heat Waves|other uses|Heat wave (disambiguation)}}
 {{Use British English|date=August 2023}}
 {{Use dmy dates|date=June 2021}}
 [[File:Heat Wave.jpg|thumb|upright=1.5|A [[High-pressure area|high pressure system]] in the [[upper atmosphere]] traps heat near the ground, forming a heat wave (for North America in this example)]]
 [[File:Heatwave in London (9217).jpg|thumb|Scorched grass in Greenwich Park, London, England, during a heatwave in August 2022.]]
-A '''heat wave''' or '''heatwave''', sometimes described as '''extreme heat''', is a period of abnormally hot weather <ref name=":42" />{{rp|2911}} that lasts for multiple days. A heat wave is usually measured relative to the usual climate in the area and to normal temperatures for the season.<ref>{{cite journal |doi=10.1175/1520-0450(2001)040<0762:OTDOAH>2.0.CO;2 |year=2001 |volume=40 |issue=4 |pages=762–775 |title=On the Definition of a Heat Wave |journal=Journal of Applied Meteorology |last1=Robinson |first1=Peter J |bibcode=2001JApMe..40..762R |doi-access=free }}</ref> The main difficulties with this broad definition emerge when one must quantify what the 'normal' temperature state is, and what the spatial extent of the event may or must be. Temperatures that humans from a hotter climate consider normal can be regarded as a heat wave in a cooler area. This would be the case if the warm temperatures are outside the normal [[climate]] pattern for that area. Heat waves have become more frequent, and more intense over land, across almost every area on Earth since the 1950s, the increase in frequency and duration being caused by [[climate change]].<ref name="SPM IPCC 2021" />{{rp|8–10}}<ref>Thompson, Andrea, [https://www.scientificamerican.com/article/this-summers-record-breaking-heat-waves-would-not-have-happened-without-climate-change/ "This Summer’s Record-Breaking Heat Waves Would Not Have Happened without Climate Change"], ''[[Scientific American]]'' 25 July 2023</ref>
+A '''heat wave''' or '''heatwave''', sometimes described as '''extreme heat''', is a period of abnormally hot weather <ref name=":42" />{{rp|2911}} that lasts for multiple days. A heat wave is usually measured relative to the usual climate in the area and to normal temperatures for the season.<ref>{{cite journal |doi=10.1175/1520-0450(2001)040<0762:OTDOAH>2.0.CO;2 |year=2001 |volume=40 |issue=4 |pages=762–775 |title=On the Definition of a Heat Wave |journal=Journal of Applied Meteorology |last1=Robinson |first1=Peter J |bibcode=2001JApMe..40..762R |doi-access=free }}</ref> The main difficulties with this broad definition emerge when one must quantify what the 'normal' temperature state is, and what the spatial extent of the event may or must be. Temperatures that humans from a hotter climate consider normal can be regarded as a heat wave in a cooler area. This would be the case if the warm temperatures are outside the normal [[climate]] pattern for that area. Heat waves have become more frequent, and more intense over land, across almost every area on Earth since the 1950s, the increase in frequency and duration being caused by [[climate change]]. According to the World Meteorological Organization, heat waves continued to intensify in 2024, with record-breaking temperatures reported in Europe, North America, and China. Many regions experienced consecutive days above 45°C, highlighting the increasing frequency and severity of extreme heat events worldwide.<ref>World Meteorological Organization. "State of the Global Climate 2024." October 2024.</ref>.
 Heat waves form when a [[high-pressure area]] in the upper atmosphere strengthens and remains over a region for several days up to several weeks.<ref name=":1" /> This traps heat near the earth's surface. It is usually possible to forecast heat waves, thus allowing the authorities to issue a warning in advance.
-Heat waves have an impact on the economy. They can reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure.<ref name=":3">{{Cite web |last=Bottollier-Depois |first=Amélie |title=Deadly heatwaves threaten economies too |url=https://phys.org/news/2022-06-deadly-heatwaves-threaten-economies.html |access-date=2022-07-15 |publisher=phys.org }}</ref><ref name=":4">{{Cite journal |last1=García-León |first1=David |last2=Casanueva |first2=Ana |last3=Standardi |first3=Gabriele |last4=Burgstall |first4=Annkatrin |last5=Flouris |first5=Andreas D. |last6=Nybo |first6=Lars |date=2021-10-04 |title=Current and projected regional economic impacts of heatwaves in Europe |journal=Nature Communications |volume=12 |issue=1 |pages=5807 |bibcode=2021NatCo..12.5807G |doi=10.1038/s41467-021-26050-z |issn=2041-1723 |pmc=8490455 |pmid=34608159}}</ref> Severe heat waves have caused catastrophic crop failures and thousands of deaths from [[hyperthermia]]. They have increased the risk of [[wildfire]]s in areas with [[drought]]. They can lead to widespread electricity outages because more air conditioning is used. A heat wave counts as [[extreme weather]]. It poses danger to human health, because heat and sunlight overwhelm the [[thermoregulation in humans]].
+Heat waves have an impact on the economy. They can reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure.<ref name=":3">{{Cite web |last=Bottollier-Depois |first=Amélie |title=Deadly heatwaves threaten economies too |url=https://phys.org/news/2022-06-deadly-heatwaves-threaten-economies.html |access-date=2022-07-15 |publisher=phys.org }}</ref><ref name=":4">{{Cite journal |last1=García-León |first1=David |last2=Casanueva |first2=Ana |last3=Standardi |first3=Gabriele |last4=Burgstall |first4=Annkatrin |last5=Flouris |first5=Andreas D. |last6=Nybo |first6=Lars |date=2021-10-04 |title=Current and projected regional economic impacts of heatwaves in Europe |journal=Nature Communications |volume=12 |issue=1 |page=5807 |bibcode=2021NatCo..12.5807G |doi=10.1038/s41467-021-26050-z |issn=2041-1723 |pmc=8490455 |pmid=34608159}}</ref> Severe heat waves have caused catastrophic crop failures and thousands of deaths from [[hyperthermia]]. They have increased the risk of [[wildfire]]s in areas with [[drought]]. They can lead to widespread electricity outages because more air conditioning is used. A heat wave counts as [[extreme weather]]. It poses a danger to human health, because heat and sunlight overwhelm the [[thermoregulation in humans]].
 == Definitions ==
 {{Weather}}
 There are several definitions of heat waves:
-* The [[Intergovernmental Panel on Climate Change|IPCC]] defines ''heatwave'' as "a period of abnormally hot weather, often defined with reference to a relative temperature threshold, lasting from two days to months."<ref>{{Cite web |title=Heat Waves Explained |date=20 May 2023 |url=https://compass.rauias.com/disaster-management/heat-waves-heat-dome/}}</ref><ref name=":42">IPCC, 2022: Annex II: [https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Annex-II.pdf Glossary] [Möller, V., R. van Diemen, J.B.R. Matthews, C. Méndez, S. Semenov, J.S. Fuglestvedt, A. Reisinger (eds.)]. In: [https://www.ipcc.ch/report/ar6/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, pp. 2897–2930, {{doi|10.1017/9781009325844.029}}.</ref>{{rp|2911}}
+* The [[Intergovernmental Panel on Climate Change|IPCC]] defines a ''heatwave'' as "a period of abnormally hot weather, often defined with reference to a relative temperature threshold, lasting from two days to months."<ref>{{Cite web |title=Heat Waves Explained |date=20 May 2023 |url=https://compass.rauias.com/disaster-management/heat-waves-heat-dome/}}</ref><ref name=":42">IPCC, 2022: Annex II: [https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Annex-II.pdf Glossary] [Möller, V., R. van Diemen, J.B.R. Matthews, C. Méndez, S. Semenov, J.S. Fuglestvedt, A. Reisinger (eds.)]. In: [https://www.ipcc.ch/report/ar6/wg2/ Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, pp. 2897–2930, {{doi|10.1017/9781009325844.029}}.</ref>{{rp|2911}}
 * A definition based on the ''Heat Wave Duration Index'' is that a heat wave occurs when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by {{convert|5|C-change|0|lk=on}}, the normal period being 1961–1990.<ref>{{cite journal |last=Frich |first= A. |author2=L.V. Alexander |author3=P. Della-Marta |author4=B. Gleason |author5=M. Haylock |author6=A.M.G. Klein Tank |author7=T. Peterson |date=January 2002 |title=Observed coherent changes in climatic extremes during the second half of the twentieth century |journal=Climate Research |volume= 19 |pages=193–212 |url=http://www.vsamp.com/resume/publications/Frich_et_al.pdf |doi=10.3354/cr019193|bibcode=2002ClRes..19..193F |doi-access=free }}</ref> The same definition is used by the [[World Meteorological Organization]].<ref name=":2">{{Cite web |title=Heat wave meteorology |url=https://www.britannica.com/science/heat-wave-meteorology |access-date=2019-04-01 |publisher=Encyclopedia Britannica }}</ref>
-* A definition from the ''Glossary of Meteorology'' is:<ref name="Glossary of Meteorology">{{cite book |last=Glickman |first=Todd S. |title=Glossary of Meteorology |publisher=American Meteorological Society |date= 2000 |isbn=9781878220493 }}</ref> "A period of abnormally and uncomfortably hot and usually humid weather."
+* A definition from the ''Glossary of Meteorology'' is:<ref name="Glossary of Meteorology">{{cite book |last=Glickman |first=Todd S. |title=Glossary of Meteorology |publisher=American Meteorological Society |date= 2000 |isbn=978-1-878220-49-3 }}</ref> "A period of abnormally and uncomfortably hot and usually humid weather."
-* ''Marine heatwaves'' are generally described as prolonged discrete periods of unusually warm sea surface temperatures in a specific region. At this time the most commonly accepted definition is that proposed by Hobday et. al.<ref>{{cite journal|last=Hobday |first=A.J. |display-authors=etal|date=2018|title=Categorizing and naming marine heatwaves. |journal=Oceanography |volume=31 |issue=2 |pages=162–173}}</ref> which refers to an algorithm that uses percentile values for temperatures, and defines a threshold set as the 90th percentile for a given day of the year, above which one can say a marine heatwave is occurring. This definition can be used with temperature data acquired anywhere in the world, allowing for comparisons across different observations and latitudes.
+* ''Marine heatwaves'' are generally described as prolonged discrete periods of unusually warm sea surface temperatures in a specific region. At this time the most commonly accepted definition is that proposed by Hobday et. al.<ref>{{cite journal|last=Hobday |first=A.J. |display-authors=etal|date=2018|title=Categorizing and naming marine heatwaves. |journal=Oceanography |volume=31 |issue=2 |pages=162–173|doi=10.5670/oceanog.2018.205 |bibcode=2018Ocgpy..31b.205H |hdl=1959.4/unsworks_57530 |hdl-access=free }}</ref> which refers to an algorithm that uses percentile values for temperatures, and defines a threshold set as the 90th percentile for a given day of the year, above which one can say a marine heatwave is occurring. This definition can be used with temperature data acquired anywhere in the world, allowing for comparisons across different observations and latitudes.
 === Definitions by country ===
 ==== Europe ====
-Denmark defines a national heat wave (''hedebølge'') as a period of at least 3 consecutive days in which the average maximum temperature across more than half the country exceeds {{convert|28|°C|°F|1}}. The [[Danish Meteorological Institute]] also has a definition for a "warmth wave" (''varmebølge''). It defines this using the same criteria for a {{convert|25|°C|°F|1}} temperature.<ref>{{cite web|url=http://www.dmi.dk/dmi/danmark_faar_varme-_og_hedeboelge |title=Danmark får varme- og hedebølge |language=da |publisher=Danish Meteorological Institute |date=22 July 2008 |access-date=18 July 2013 |url-status=dead |archive-url=https://web.archive.org/web/20080723170544/http://www.dmi.dk/dmi/danmark_faar_varme-_og_hedeboelge |archive-date=23 July 2008 }}</ref> Sweden defines a heat wave as at least five days in a row with a daily high exceeding {{convert|25|°C|°F|1}}.<ref>{{cite web|url=http://www.smhi.se/kunskapsbanken/klimat/varmebolja-1.22372 |title=Värmebölja Klimat: Kunskapsbanken SMHI |language=sv |publisher=Smhi.se |access-date=17 July 2013}}</ref>
+Denmark defines a national heat wave (''hedebølge'') as a period of at least 3 consecutive days in which the average maximum temperature across more than half the country exceeds {{convert|28|°C|°F|1}}. The [[Danish Meteorological Institute]] also has a definition for a "warmth wave" (''varmebølge''). It defines this using the same criteria for a {{convert|25|°C|°F|1}} temperature.<ref>{{cite web|url=http://www.dmi.dk/dmi/danmark_faar_varme-_og_hedeboelge |title=Danmark får varme- og hedebølge |language=da |publisher=Danish Meteorological Institute |date=22 July 2008 |access-date=18 July 2013 |archive-url=https://web.archive.org/web/20080723170544/http://www.dmi.dk/dmi/danmark_faar_varme-_og_hedeboelge |archive-date=23 July 2008 }}</ref> Sweden defines a heat wave as at least five days in a row with a daily high exceeding {{convert|25|°C|°F|1}}.<ref>{{cite web|url=http://www.smhi.se/kunskapsbanken/klimat/varmebolja-1.22372 |title=Värmebölja Klimat: Kunskapsbanken SMHI |language=sv |publisher=Smhi.se |access-date=17 July 2013}}</ref>
-In Greece, the [http://www.hnms.gr/emy/el/ Hellenic National Meteorological Service] defines a heat wave as occurring over three consecutive days with temperatures at 39&nbsp;°C (102&nbsp;°F) or higher. In the same period the minimum temperature is {{convert|26|°C|°F}} or more. During this period, there are either no winds or only weak winds. These conditions occur in a broad area.
+In Greece, the [[Hellenic National Meteorological Service]] defines a heat wave as occurring over three consecutive days with temperatures at 39&nbsp;°C (102&nbsp;°F) or higher. In the same period the minimum temperature is {{convert|26|°C|°F}} or more. During this period, there are either no winds or only weak winds. These conditions occur in a broad area.{{Citation needed|date=December 2025}}
 The Netherlands defines a heat wave as a period of at least five consecutive days in which the maximum temperature in [[De Bilt]] exceeds {{convert|25|°C|°F}}. During this period the maximum temperature in De Bilt must exceed {{convert|30|°C|°F}} for at least three days. Belgium also uses this definition of a heat wave with [[Ukkel]] as a reference point. So does Luxembourg.
@@ Line 34: / Line 33: @@
 ==== North America ====
-In the United States, definitions also vary by region. They usually involve a period of at least two or more days of excessively hot weather.<ref>{{cite web |url=http://www.weather.gov/glossary/index.php?word=heat+wave |title=Glossary |publisher=NOAA's National Weather Service |date=25 June 2009 |access-date=17 July 2013}}</ref> In the [[Northeastern United States|Northeast]], a heat wave is typically when the temperature reaches or exceeds {{convert|90|°F|°C|1}} for three or more consecutive days. This is not always the case. This is because the high temperature ties in with humidity levels to determine a heat index threshold.<ref>{{cite web |last=Singer |first=Stephen |title=Half the country wilts under unrelenting heat |url=http://old.news.yahoo.com/s/ap/us_hot_weather |publisher=Yahoo! News |url-status=dead |archive-url=https://archive.today/20120716024044/http://old.news.yahoo.com/s/ap/us_hot_weather |archive-date=16 July 2012 |df=dmy-all}}</ref> The same does not apply to drier climates. A heat storm is a Californian term for an extended heat wave. Heat storms occur when the temperature reaches {{convert|100|°F|°C|1}} for three or more consecutive days over a wide area (tens of thousands of square miles).<ref>{{cite web|title=Staying Cool and Safe|publisher=[[Pacific Gas and Electric Company]]|location=Oakland, California|date=24 March 2017|accessdate=26 June 2023|url=https://www.pge.com/includes/docs/pdfs/myhome/edusafety/seasonal/coolingcenters/staying_cooling_and_safe_english.pdf|archive-date=27 June 2023|archive-url=https://web.archive.org/web/20230627064913/https://www.pge.com/includes/docs/pdfs/myhome/edusafety/seasonal/coolingcenters/staying_cooling_and_safe_english.pdf|url-status=dead}}</ref> The [[National Weather Service]] issues [[heat advisory|heat advisories]] and [[excessive heat warning]]s when it expects unusual periods of hot weather.
+In the United States, definitions also vary by region. They usually involve a period of at least two or more days of excessively hot weather.<ref>{{cite web |url=http://www.weather.gov/glossary/index.php?word=heat+wave |title=Glossary |publisher=NOAA's National Weather Service |date=25 June 2009 |access-date=17 July 2013}}</ref> In the [[Northeastern United States|Northeast]], a heat wave is typically when the temperature reaches or exceeds {{convert|90|°F|°C|1}} for three or more consecutive days. This is not always the case. This is because the high temperature ties in with humidity levels to determine a heat index threshold.<ref>{{cite web |last=Singer |first=Stephen |title=Half the country wilts under unrelenting heat |url=http://old.news.yahoo.com/s/ap/us_hot_weather |publisher=Yahoo! News |archive-url=https://archive.today/20120716024044/http://old.news.yahoo.com/s/ap/us_hot_weather |archive-date=16 July 2012 }}</ref> The same does not apply to drier climates. A heat storm is a Californian term for an extended heat wave. Heat storms occur when the temperature reaches {{convert|100|°F|°C|1}} for three or more consecutive days over a wide area (tens of thousands of square miles).<ref>{{cite web|title=Staying Cool and Safe|publisher=[[Pacific Gas and Electric Company]]|location=Oakland, California|date=24 March 2017|access-date=26 June 2023|url=https://www.pge.com/includes/docs/pdfs/myhome/edusafety/seasonal/coolingcenters/staying_cooling_and_safe_english.pdf|archive-date=27 June 2023|archive-url=https://web.archive.org/web/20230627064913/https://www.pge.com/includes/docs/pdfs/myhome/edusafety/seasonal/coolingcenters/staying_cooling_and_safe_english.pdf}}</ref> The [[National Weather Service]] issues [[heat advisory|heat advisories]] and [[excessive heat warning]]s when it expects unusual periods of hot weather.
 In Canada, heat waves are defined using the daily maximum and minimum temperatures, and in most of the country, the [[humidex]] as well, exceeding a regional threshold for two or more days. The threshold in which daily maximum temperatures must exceed ranges between {{convert|28|°C|°F}} in Newfoundland and {{convert|35|°C|°F}} in interior British Columbia, though this threshold is much lower in Nunavut, ranging between {{convert|22|°C|°F}} and {{convert|26|°C|°F}}.<ref>{{cite web |date=31 Jul 2024|title=Criteria for public weather alerts|url=https://www.canada.ca/en/environment-climate-change/services/types-weather-forecasts-use/public/criteria-alerts.html#heat|access-date=1 Feb 2025 |publisher=Environment and Climate Change Canada}}</ref>
 ====Oceania====
-In Adelaide, South Australia, a heat wave is five consecutive days at or above {{convert|35|°C|°F}}, or three consecutive days at or over {{convert|40|°C|°F}}.<ref>{{cite web |url=http://www.bom.gov.au/announcements/media_releases/sa/20100115_First_Heatwave_SA_Jan.shtml |title=Extreme Heat Services for South Australia |publisher=Bureau of Meteorology |date=15 January 2010 |access-date=17 July 2013}}</ref> The [[Bureau of Meteorology|Australian Bureau of Meteorology]] defines a heat wave as three or more days of unusual maximum and minimum temperatures.<ref name=":0">{{Cite web|title = Australia Weather and Warnings|url = http://www.bom.gov.au/weather-services/about/heatwave-forecast.shtml|publisher = Bureau of Meteorology|access-date = 2016-01-17|language = en|archive-date = 16 October 2015|archive-url = https://web.archive.org/web/20151016140923/http://www.bom.gov.au/weather-services/about/heatwave-forecast.shtml|url-status = dead}}</ref> Before this new Pilot Heatwave Forecast there was no national definition for heat waves or measures of heat wave severity.<ref name=":0" />
+In Adelaide, South Australia, a heat wave is five consecutive days at or above {{convert|35|°C|°F}}, or three consecutive days at or over {{convert|40|°C|°F}}.<ref>{{cite web |date=15 January 2010 |title=Extreme Heat Services for South Australia |url=http://www.bom.gov.au/announcements/media_releases/sa/20100115_First_Heatwave_SA_Jan.shtml |archive-url=https://web.archive.org/web/20170118053557/bom.gov.au/announcements/media_releases/sa/20100115_First_Heatwave_SA_Jan.shtml |archive-date=2017-01-18 |access-date=17 July 2013 |publisher=Bureau of Meteorology}}</ref> The [[Bureau of Meteorology|Australian Bureau of Meteorology]] defines a heat wave as three or more days of unusual maximum and minimum temperatures.<ref name=":0">{{Cite web|title = Australia Weather and Warnings|url = http://www.bom.gov.au/weather-services/about/heatwave-forecast.shtml|publisher = Bureau of Meteorology|access-date = 2016-01-17|language = en|archive-date = 16 October 2015|archive-url = https://web.archive.org/web/20151016140923/http://www.bom.gov.au/weather-services/about/heatwave-forecast.shtml}}</ref> Before this new Pilot Heatwave Forecast there was no national definition for heat waves or measures of heat wave severity.<ref name=":0" />
 In [[New Zealand]], heat waves thresholds depend on local climatology, with the temperature threshold ranging between {{convert|27|°C|°F}} in Greymouth and {{convert|32|°C|°F}} in Gisborne.<ref>{{cite web |date=2024|title=Heat|url=https://getready.govt.nz/emergency/heat|access-date=1 Feb 2025 |publisher=Get Ready - National Emergency Management Agency}}</ref>
 == Marine Heatwaves ==
+{{Main|Marine heatwave}}
-Marine heatwaves have become a prominent subject of research in recent years, reflecting the fact that since the turn of this century many ocean areas have experienced peaks of temperatures, along with more frequent, more intense, more prolonged warming events than ever met on record.<ref>Marine heatwaves in the Mediterranean Sea and beyond - an overview. 2024. pp. 5-24 in ''CIESM Monograph 51’’ ''(F. Briand, Ed.) ISSN 1726-5886'' [https://www.researchgate.net/publication/384727584]''</ref> The genesis of marine heatwaves is mainly driven by a combination of oceanic and atmospheric factors, often triggered by high pressure systems that will reduce cloud cover and increase solar absorption by the sea surface. Human-induced climate change appears bound to play a growing role in the development of marine heatwaves, with increasing impacts on marine ecosystems, such as mass mortality in benthic communities, coral bleaching events, disruptions in fishery catches, and shifts in species distributions.
+Marine heatwaves have become a prominent subject of research in recent years, reflecting the fact that since the turn of this century many ocean areas have experienced peaks of temperatures, along with more frequent, more intense, and more prolonged warming events than ever met on record.<ref>Marine heatwaves in the Mediterranean Sea and beyond - an overview. 2024. pp. 5-24 in ''CIESM Monograph 51'' (F. Briand, Ed.) ISSN 1726-5886 ''[https://www.researchgate.net/publication/384727584]''</ref> The genesis of marine heatwaves is mainly driven by a combination of oceanic and atmospheric factors, often triggered by high pressure systems that will reduce cloud cover and increase solar absorption by the sea surface. Human-induced climate change appears bound to play a growing role in the development of marine heatwaves, with increasing impacts on marine ecosystems, such as mass mortality in benthic communities, coral bleaching events, disruptions in fishery catches, and shifts in species distributions.
 == Observations ==
@@ Line 52: / Line 51: @@
 | image1= 1951+ Percent of global area at temperature records - Seasonal comparison - NOAA.svg |caption1= New high temperature records have outpaced new low temperature records on a growing portion of Earth's surface.<ref name=NOAA_October>{{cite web |title=Mean Monthly Temperature Records Across the Globe / Timeseries of Global Land and Ocean Areas at Record Levels for October from 1951-2023 |url=https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202310/supplemental/page-3 |publisher=National Centers for Environmental Information (NCEI) NCEI.NOAA.gov of the National Oceanic and Atmospheric Administration (NOAA)|archive-url=https://web.archive.org/web/20231116185412/https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202310/supplemental/page-3 |archive-date=16 November 2023 |date=November 2023 |url-status=live}} (change "202310" in URL to see years other than 2023, and months other than 10=October)</ref>
 | image2= 20211109 Frequency of extreme weather for different degrees of global warming - bar chart IPCC AR6 WG1 SPM.svg |caption2= Large increases in both the frequency and intensity of [[extreme weather]] events (for increasing degrees of global warming) are expected.<ref name="SPM IPCC 2021">IPCC, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf Summary for Policymakers]. In: [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 3−32, {{doi|10.1017/9781009157896.001}}</ref>{{rp|18}}
-}}[[File:Map of increasing heatwave trends over the midlatitudes and Europe.webp|thumb|upright=1.35|Map of increasing heat wave trends (frequency and cumulative intensity) over the midlatitudes and Europe, July–August 1979–2020<ref>{{cite journal |last1=Rousi |first1=Efi |last2=Kornhuber |first2=Kai |last3=Beobide-Arsuaga |first3=Goratz |last4=Luo |first4=Fei |last5=Coumou |first5=Dim |date=4 July 2022 |title=Accelerated western European heatwave trends linked to more-persistent double jets over Eurasia |journal=Nature Communications |volume=13 |issue=1 |pages=3851 |bibcode=2022NatCo..13.3851R |doi=10.1038/s41467-022-31432-y |pmc=9253148 |pmid=35788585 |doi-access=free}}
+}}[[File:Map of increasing heatwave trends over the midlatitudes and Europe.webp|thumb|upright=1.35|Map of increasing heat wave trends (frequency and cumulative intensity) over the midlatitudes and Europe, July–August 1979–2020<ref>{{cite journal |last1=Rousi |first1=Efi |last2=Kornhuber |first2=Kai |last3=Beobide-Arsuaga |first3=Goratz |last4=Luo |first4=Fei |last5=Coumou |first5=Dim |date=4 July 2022 |title=Accelerated western European heatwave trends linked to more-persistent double jets over Eurasia |journal=Nature Communications |volume=13 |issue=1 |page=3851 |bibcode=2022NatCo..13.3851R |doi=10.1038/s41467-022-31432-y |pmc=9253148 |pmid=35788585 |doi-access=free}}
-* News report: {{cite news |last1=Fountain |first1=Henry |date=18 July 2022 |title=Why Europe Is Becoming a Heat Wave Hot Spot |work=The New York Times |url=https://www.nytimes.com/2022/07/19/climate/europe-heat-wave-science.html |access-date=21 August 2022}}</ref>]]It is possible to compare heat waves in different regions of the world with different climates thanks to a general indicator that appeared in 2015.<ref>{{cite journal |last1=Russo |first1=Simone |last2=Sillmann |first2=Jana |last3=Fischer |first3=Erich M |year=2015 |title=Top ten European heatwaves since 1950 and their occurrence in the coming decades |url=https://www.research-collection.ethz.ch/bitstream/20.500.11850/109725/2/Russo_109725.pdf |journal=Environmental Research Letters |volume=10 |issue=12 |pages=124003 |bibcode=2015ERL....10l4003R |doi=10.1088/1748-9326/10/12/124003 |doi-access=free}}</ref> With these indicators, experts estimated heat waves at the global scale from 1901 to 2010. They found a substantial and sharp increase in the number of affected areas in the last two decades.<ref>{{cite journal |last1=Zampieri |first1=Matteo |last2=Russo |first2=Simone |last3=Di Sabatino |first3=Silvana |last4=Michetti |first4=Melania |last5=Scoccimarro |first5=Enrico |last6=Gualdi |first6=Silvio |year=2016 |title=Global assessment of heatwave magnitudes from 1901 to 2010 and implications for the river discharge of the Alps |journal=Science of the Total Environment |volume=571 |pages=1330–9 |bibcode=2016ScTEn.571.1330Z |doi=10.1016/j.scitotenv.2016.07.008 |pmid=27418520}}</ref>
+* News report: {{cite news |last1=Fountain |first1=Henry |date=18 July 2022 |title=Why Europe Is Becoming a Heat Wave Hot Spot |work=The New York Times |url=https://www.nytimes.com/2022/07/19/climate/europe-heat-wave-science.html |access-date=21 August 2022}}</ref>]]It is possible to compare heat waves in different regions of the world with different climates thanks to a general indicator that appeared in 2015.<ref>{{cite journal |last1=Russo |first1=Simone |last2=Sillmann |first2=Jana |last3=Fischer |first3=Erich M |year=2015 |title=Top ten European heatwaves since 1950 and their occurrence in the coming decades |url=https://www.research-collection.ethz.ch/bitstream/20.500.11850/109725/2/Russo_109725.pdf |journal=Environmental Research Letters |volume=10 |issue=12 |article-number=124003 |bibcode=2015ERL....10l4003R |doi=10.1088/1748-9326/10/12/124003 |doi-access=free}}</ref> With these indicators, experts estimated heat waves at the global scale from 1901 to 2010. They found a substantial and sharp increase in the number of affected areas in the last two decades.<ref>{{cite journal |last1=Zampieri |first1=Matteo |last2=Russo |first2=Simone |last3=Di Sabatino |first3=Silvana |last4=Michetti |first4=Melania |last5=Scoccimarro |first5=Enrico |last6=Gualdi |first6=Silvio |year=2016 |title=Global assessment of heatwave magnitudes from 1901 to 2010 and implications for the river discharge of the Alps |journal=Science of the Total Environment |volume=571 |pages=1330–9 |bibcode=2016ScTEn.571.1330Z |doi=10.1016/j.scitotenv.2016.07.008 |pmid=27418520}}</ref>
-One study in 2021 investigated 13,115 cities. It found that extreme heat exposure of a [[wet bulb globe temperature]] above 30 Celsius tripled between 1983 and 2016, and if the effect of population growth (increasing the [[urban heat island]] effect) during those years is excluded, the exposure increased a further 50%. The researchers compiled a comprehensive list of past urban extreme heat events.<ref>{{cite news |last1=Henson |first1=Bob |title=Exposure to extreme urban heat has tripled worldwide since the 1980s, study finds |newspaper=Washington Post |url=https://www.washingtonpost.com/weather/2021/11/09/extreme-heat-exposure-urban-climate/ |access-date=15 November 2021}}</ref><ref>{{cite journal |last1=Tuholske |first1=Cascade |last2=Caylor |first2=Kelly |last3=Funk |first3=Chris |last4=Verdin |first4=Andrew |last5=Sweeney |first5=Stuart |last6=Grace |first6=Kathryn |last7=Peterson |first7=Pete |last8=Evans |first8=Tom |date=12 October 2021 |title=Global urban population exposure to extreme heat |journal=Proceedings of the National Academy of Sciences |language=en |volume=118 |issue=41 |pages=e2024792118 |bibcode=2021PNAS..11824792T |doi=10.1073/pnas.2024792118 |issn=0027-8424 |pmc=8521713 |pmid=34607944 |doi-access=free}}</ref>
+One study in 2021 investigated 13,115 cities. It found that extreme heat exposure of a [[wet bulb globe temperature]] above 30 Celsius tripled between 1983 and 2016, and if the effect of population growth (increasing the [[urban heat island]] effect) during those years is excluded, the exposure increased a further 50%. The researchers compiled a comprehensive list of past urban extreme heat events.<ref>{{cite news |last1=Henson |first1=Bob |title=Exposure to extreme urban heat has tripled worldwide since the 1980s, study finds |newspaper=Washington Post |url=https://www.washingtonpost.com/weather/2021/11/09/extreme-heat-exposure-urban-climate/ |access-date=15 November 2021}}</ref><ref>{{cite journal |last1=Tuholske |first1=Cascade |last2=Caylor |first2=Kelly |last3=Funk |first3=Chris |last4=Verdin |first4=Andrew |last5=Sweeney |first5=Stuart |last6=Grace |first6=Kathryn |last7=Peterson |first7=Pete |last8=Evans |first8=Tom |date=12 October 2021 |title=Global urban population exposure to extreme heat |journal=Proceedings of the National Academy of Sciences |language=en |volume=118 |issue=41 |article-number=e2024792118 |bibcode=2021PNAS..11824792T |doi=10.1073/pnas.2024792118 |issn=0027-8424 |pmc=8521713 |pmid=34607944 |doi-access=free}}</ref>
 == Causes ==
-Heat waves form when a [[High-pressure area|high pressure area]] at an altitude of {{convert|3000|-|7600|m|abbr=off}} strengthens and remains over a region for several days and up to several weeks.<ref name=":1">{{Cite web |url=https://www.weather.gov/jetstream/hi |title=NWS JetStream - Heat Index |publisher=US Department of Commerce NOAA weather.gov |access-date=2019-02-09}}</ref> This is common in summer in both the Northern and Southern Hemispheres. This is because the [[jet stream]] 'follows the sun'. The high pressure area is on the equator side of the jet stream in the upper layers of the atmosphere.
+Heat waves form when a [[High-pressure area|high pressure area]] at an altitude of {{convert|3000|-|7600|m|abbr=off}} strengthens and remains over a region for several days and up to several weeks.<ref name=":1">{{Cite web |last=J |title=NWS JetStream - Heat Index |url=https://www.weather.gov/jetstream/hi |access-date=2019-02-09 |publisher=US Department of Commerce NOAA weather.gov}}</ref> This is common in summer in both the Northern and Southern Hemispheres. This is because the [[jet stream]] 'follows the sun'. The high pressure area is on the equator side of the jet stream in the upper layers of the atmosphere.
-Weather patterns are generally slower to change in summer than in winter. So, this upper level high pressure also moves slowly. Under high pressure, the air sinks toward the surface. It warms and dries [[Adiabatic process#Adiabatic heating and cooling|adiabatically]]. This inhibits [[Atmospheric convection|convection]] and prevents the formation of clouds. A reduction of clouds increases the [[shortwave radiation]] reaching the surface. A [[Low-pressure area|low pressure]] area at the surface leads to surface wind from lower latitudes that brings warm air, enhancing the warming. The surface winds could also blow from the hot continental interior towards the coastal zone. This would lead to heat waves on the coast. They could also blow from high towards low elevations. This enhances the subsidence or sinking of the air and therefore the adiabatic warming.<ref>{{cite journal |journal=Journal of Climate |title=A Model Study of Heat Waves over North America: Meteorological Aspects and Projections for the Twenty-First Century |volume=25 |pages=4761–4784 |year=2012 |last1=Lau |first1=N |last2=Nath |first2=Mary Jo|issue=14 |doi=10.1175/JCLI-D-11-00575.1 |bibcode=2012JCli...25.4761L |doi-access=free }}</ref><ref>{{cite web |title=Heat Index |publisher=US National Weather Service |url=http://www.srh.noaa.gov/jetstream/global/hi.htm}}</ref>
+Weather patterns are generally slower to change in summer than in winter. So, this upper level high pressure also moves slowly. Under high pressure, the air sinks toward the surface. It warms and dries [[Adiabatic process#Adiabatic heating and cooling|adiabatically]]. This inhibits [[Atmospheric convection|convection]] and prevents the formation of clouds. A reduction of clouds increases the [[shortwave radiation]] reaching the surface. A [[Low-pressure area|low pressure]] area at the surface leads to surface wind from lower latitudes that brings warm air, enhancing the warming. The surface winds could also blow from the hot continental interior towards the coastal zone. This would lead to heat waves on the coast. They could also blow from high towards low elevations. This enhances the subsidence or sinking of the air and therefore the adiabatic warming.<ref>{{cite journal |journal=Journal of Climate |title=A Model Study of Heat Waves over North America: Meteorological Aspects and Projections for the Twenty-First Century |volume=25 |pages=4761–4784 |year=2012 |last1=Lau |first1=N |last2=Nath |first2=Mary Jo|issue=14 |doi=10.1175/JCLI-D-11-00575.1 |bibcode=2012JCli...25.4761L |doi-access=free }}</ref><ref>{{cite web |title=Heat Index |url=http://www.srh.noaa.gov/jetstream/global/hi.htm |archive-url=https://web.archive.org/web/20170210164559/http://www.srh.noaa.gov/jetstream/global/hi.html |archive-date=2017-02-10 |publisher=US National Weather Service}}</ref>
-In the eastern regions of the United States a heat wave can occur when a [[High-pressure area|high pressure system]] originating in the Gulf of Mexico becomes stationary just off the Atlantic Seaboard. Hot humid air masses form over the Gulf of Mexico and the Caribbean Sea. At the same time hot dry air masses form over the desert Southwest and northern Mexico. The southwest winds on the back side of the high continue to pump hot, humid Gulf air northeastwards. This results in a spell of hot and humid weather for much of the eastern United States and into southeastern Canada.<ref>{{cite web|title=Heat Index |publisher=Pasquotank County, NC, U. S. Website |url=http://www.co.pasquotank.nc.us/departments/911/webpage/heatwaves.htm |url-status=dead |archive-url=https://web.archive.org/web/20120318154040/http://www.co.pasquotank.nc.us/departments/911/webpage/heatwaves.htm |archive-date=18 March 2012 }}</ref>
+In the eastern regions of the United States a heat wave can occur when a [[High-pressure area|high pressure system]] originating in the Gulf of Mexico becomes stationary just off the Atlantic Seaboard. Hot humid air masses form over the Gulf of Mexico and the Caribbean Sea. At the same time hot dry air masses form over the desert Southwest and northern Mexico. The southwest winds on the back side of the high continue to pump hot, humid Gulf air northeastwards. This results in a spell of hot and humid weather for much of the eastern United States and into southeastern Canada.<ref>{{cite web|title=Heat Index |publisher=Pasquotank County, NC, U. S. Website |url=http://www.co.pasquotank.nc.us/departments/911/webpage/heatwaves.htm |archive-url=https://web.archive.org/web/20120318154040/http://www.co.pasquotank.nc.us/departments/911/webpage/heatwaves.htm |archive-date=18 March 2012 }}</ref>
-In the [[Western Cape]] Province of South Africa, a heat wave can occur when the [[low-pressure area]] offshore and the [[high-pressure area]] inland combine to form a [[bergwind]]. The air warms as it descends from the Karoo interior. The temperature will rise about 10 Celsius from the interior to the coast. Humidity is usually very low. The temperature can be over 40 Celsius in summer. The highest temperature recorded in South Africa (51.5 Celsius) occurred one summer during a berg wind along the Eastern Cape coastline.<ref>{{cite web |title=Bergwind Info |publisher=1stweather.com |url=http://www.1stweather.com/regional/education/bergwind.shtml |url-status=dead |archive-url=https://web.archive.org/web/20120415080019/http://www.1stweather.com/regional/education/bergwind.shtml |archive-date=15 April 2012 |df=dmy-all }}</ref><ref>{{cite web|title=Natural Hazards - Heat Wave|publisher=City of Cape Town, South Africa Website|url=http://www.capetown.gov.za/en/DRM/Pages/HeatWave.aspx|url-status=dead|archive-url=https://web.archive.org/web/20120608111607/http://www.capetown.gov.za/en/DRM/Pages/HeatWave.aspx|archive-date=8 June 2012|df=dmy-all}}</ref>
+In the [[Western Cape]] Province of South Africa, a heat wave can occur when the [[low-pressure area]] offshore and the [[high-pressure area]] inland combine to form a [[bergwind]]. The air warms as it descends from the Karoo interior. The temperature will rise about 10 Celsius from the interior to the coast. Humidity is usually very low. The temperature can be over 40 Celsius in summer. The highest temperature recorded in South Africa (51.5 Celsius) occurred one summer during a berg wind along the Eastern Cape coastline.<ref>{{cite web |title=Bergwind Info |publisher=1stweather.com |url=http://www.1stweather.com/regional/education/bergwind.shtml |archive-url=https://web.archive.org/web/20120415080019/http://www.1stweather.com/regional/education/bergwind.shtml |archive-date=15 April 2012 }}</ref><ref>{{cite web|title=Natural Hazards - Heat Wave|publisher=City of Cape Town, South Africa Website|url=http://www.capetown.gov.za/en/DRM/Pages/HeatWave.aspx|archive-url=https://web.archive.org/web/20120608111607/http://www.capetown.gov.za/en/DRM/Pages/HeatWave.aspx|archive-date=8 June 2012}}</ref>
-The level of [[soil moisture]] can intensify heat waves in Europe.<ref name="Miralles n/a–n/a">{{Cite journal |last1=Miralles |first1=D. G. |last2=van den Berg |first2=M. J. |last3=Teuling |first3=A. J. |last4=de Jeu |first4=R. A. M. |date=November 2012 |title=Soil moisture-temperature coupling: A multiscale observational analysis |url=https://doi.org/10.1029/2012GL053703 |journal=Geophysical Research Letters |volume=39 |issue=21 |pages=n/a |doi=10.1029/2012gl053703 |bibcode=2012GeoRL..3921707M |s2cid=53668167 |issn=0094-8276}}</ref><ref>{{Cite journal |last1=Seneviratne |first1=Sonia I. |last2=Corti |first2=Thierry |last3=Davin |first3=Edouard L. |last4=Hirschi |first4=Martin |last5=Jaeger |first5=Eric B. |last6=Lehner |first6=Irene |last7=Orlowsky |first7=Boris |last8=Teuling |first8=Adriaan J. |date=2010-05-01 |title=Investigating soil moisture–climate interactions in a changing climate: A review |url=https://www.sciencedirect.com/science/article/pii/S0012825210000139 |journal=Earth-Science Reviews |language=en |volume=99 |issue=3 |pages=125–161 |doi=10.1016/j.earscirev.2010.02.004 |bibcode=2010ESRv...99..125S |issn=0012-8252|url-access=subscription }}</ref> Low soil moisture leads to a number of complex feedback mechanisms. These in turn can result in increased surface temperatures. One of the main mechanisms is reduced evaporative cooling of the atmosphere.<ref name="Miralles n/a–n/a"/> When water evaporates, it consumes energy. So, it will lower the surrounding temperature. If the soil is very dry, then incoming radiation from the sun will warm the air. But there will be little or no cooling effect from moisture evaporating from the soil.
+The level of [[soil moisture]] can intensify heat waves in Europe.<ref name="Miralles n/a–n/a">{{Cite journal |last1=Miralles |first1=D. G. |last2=van den Berg |first2=M. J. |last3=Teuling |first3=A. J. |last4=de Jeu |first4=R. A. M. |date=November 2012 |title=Soil moisture-temperature coupling: A multiscale observational analysis |journal=Geophysical Research Letters |volume=39 |issue=21 |pages=n/a |doi=10.1029/2012gl053703 |bibcode=2012GeoRL..3921707M |s2cid=53668167 |issn=0094-8276}}</ref><ref>{{Cite journal |last1=Seneviratne |first1=Sonia I. |last2=Corti |first2=Thierry |last3=Davin |first3=Edouard L. |last4=Hirschi |first4=Martin |last5=Jaeger |first5=Eric B. |last6=Lehner |first6=Irene |last7=Orlowsky |first7=Boris |last8=Teuling |first8=Adriaan J. |date=2010-05-01 |title=Investigating soil moisture–climate interactions in a changing climate: A review |url=https://www.sciencedirect.com/science/article/pii/S0012825210000139 |journal=Earth-Science Reviews |language=en |volume=99 |issue=3 |pages=125–161 |doi=10.1016/j.earscirev.2010.02.004 |bibcode=2010ESRv...99..125S |issn=0012-8252|url-access=subscription }}</ref> Low soil moisture leads to a number of complex feedback mechanisms. These in turn can result in increased surface temperatures. One of the main mechanisms is reduced evaporative cooling of the atmosphere.<ref name="Miralles n/a–n/a"/> When water evaporates, it consumes energy and therefore lowers the surrounding temperature. If the soil is very dry, then incoming radiation from the sun will warm the air. But there will be little or no cooling effect from moisture evaporating from the soil.
 === Climate change ===
@@ Line 85: / Line 84: @@
 ==== Underreporting of fatalities ====
-The number of heat fatalities is probably highly underreported. This is due to a lack of reports and to misreporting.<ref name="heat epidemiology">{{cite journal |last=Basu |first=Rupa |author2=Jonathan M. Samet |year=2002 |title=Relation between Elevated Ambient Temperature and Mortality: A Review of the Epidemiologic Evidence |journal=[[Epidemiologic Reviews]] |volume=24 |issue=2 |pages=190–202 |doi=10.1093/epirev/mxf007 |pmid=12762092 |doi-access=free}}</ref> When considering heat-related illnesses as well, actual death tolls from extreme heat may be six times higher than official figures. This is based on studies of California<ref>{{Cite web |title=Heat waves are far deadlier than we think. How California neglects this climate threat |url=https://www.latimes.com/projects/california-extreme-heat-deaths-show-climate-change-risks/ |access-date=2022-09-04 |website=Los Angeles Times |date=7 October 2021 |language=en}}</ref> and Japan.<ref>{{Cite journal |last1=Fujibe |first1=Fumiaki |last2=Matsumoto |first2=Jun |date=2021 |title=Estimation of Excess Deaths during Hot Summers in Japan |url=https://www.jstage.jst.go.jp/article/sola/17/0/17_2021-038/_article/-char/ja |journal=Scientific Online Letters on the Atmosphere |volume=17 |pages=220–223 |bibcode=2021SOLA...17..220F |doi=10.2151/sola.2021-038 |s2cid=241577645 |doi-access=free}}</ref>
+The number of heat fatalities is probably highly underreported. This is due to a lack of reports and to misreporting.<ref name="heat epidemiology">{{cite journal |last=Basu |first=Rupa |author2=Jonathan M. Samet |year=2002 |title=Relation between Elevated Ambient Temperature and Mortality: A Review of the Epidemiologic Evidence |journal=[[Epidemiologic Reviews]] |volume=24 |issue=2 |pages=190–202 |doi=10.1093/epirev/mxf007 |pmid=12762092 |doi-access=free}}</ref> When considering heat-related illnesses as well, actual death tolls from extreme heat may be six times higher than official figures. This is based on studies of California<ref>{{Cite web |title=Heat waves are far deadlier than we think. How California neglects this climate threat |url=https://www.latimes.com/projects/california-extreme-heat-deaths-show-climate-change-risks/ |access-date=2022-09-04 |website=Los Angeles Times |date=7 October 2021 |language=en}}</ref> and Japan.<ref>{{Cite journal |last1=Fujibe |first1=Fumiaki |last2=Matsumoto |first2=Jun |date=2021 |title=Estimation of Excess Deaths during Hot Summers in Japan |url=https://www.jstage.jst.go.jp/article/sola/17/0/17_2021-038/_article/-char/ja |journal=Scientific Online Letters on the Atmosphere |volume=17 |pages=220–223 |article-number=2021-038 |bibcode=2021SOLA...17..220F |doi=10.2151/sola.2021-038 |s2cid=241577645 |doi-access=free}}</ref>
 Part of the mortality during a heat wave may be due to short-term forward [[mortality displacement]]. In some heat waves there is a decrease in overall mortality in the weeks after a heat wave. These compensatory reductions in mortality suggest that heat affects people who would have died anyway, and brings their deaths forward.<ref name="pmid11401757">{{cite journal |last1=Huynen |first1=Maud M. T. E |last2=Martens |first2=Pim |last3=Schram |first3=Dieneke |last4=Weijenberg |first4=Matty P |last5=Kunst |first5=Anton E |year=2001 |title=The Impact of Heat Waves and Cold Spells on Mortality Rates in the Dutch Population |journal=Environmental Health Perspectives |volume=109 |issue=5 |pages=463–70 |doi=10.2307/3454704 |jstor=3454704 |pmc=1240305 |pmid=11401757}}</ref>
-Social institutions and structures influence the effects of risks. This factor can also help explain the underreporting of heat waves as a health risk. The deadly [[2003 European heat wave#France|French heat wave]] in 2003 showed that heat wave dangers result from a combination of natural and social factors.<ref>{{cite journal |last1=Poumadère |first1=M. |last2=Mays |first2=C. |last3=Le Mer |first3=S. |last4=Blong |first4=R. |year=2005 |title=The 2003 Heat Wave in France: Dangerous Climate Change Here and Now |url=http://www.coe.int/t/dg4/majorhazards/activites/murcia_26-27oct2009/heatwave2003_poumadere2005.pdf |journal=Risk Analysis |volume=25 |issue=6 |pages=1483–1494 |citeseerx=10.1.1.577.825 |doi=10.1111/j.1539-6924.2005.00694.x |pmid=16506977 |bibcode=2005RiskA..25.1483P |s2cid=25784074}}</ref> Social invisibility is one such factor. Heat-related deaths can occur indoors, for instance among elderly people living alone. In these cases it can be challenging to assign heat as a contributing factor.<ref>{{Cite journal |last=Ro |first=Christine |date=2022-09-01 |title=Can Japan really reach "zero deaths" from heat stroke? |url=https://www.bmj.com/content/378/bmj.o2107 |journal=BMJ |language=en |volume=378 |pages=o2107 |doi=10.1136/bmj.o2107 |issn=1756-1833 |s2cid=251954370 |doi-access=free|url-access=subscription }}</ref>
+Social institutions and structures influence the effects of risks. This factor can also help explain the underreporting of heat waves as a health risk. The deadly [[2003 European heat wave#France|French heat wave]] in 2003 showed that heat wave dangers result from a combination of natural and social factors.<ref>{{cite journal |last1=Poumadère |first1=M. |last2=Mays |first2=C. |last3=Le Mer |first3=S. |last4=Blong |first4=R. |year=2005 |title=The 2003 Heat Wave in France: Dangerous Climate Change Here and Now |url=http://www.coe.int/t/dg4/majorhazards/activites/murcia_26-27oct2009/heatwave2003_poumadere2005.pdf |journal=Risk Analysis |volume=25 |issue=6 |pages=1483–1494 |citeseerx=10.1.1.577.825 |doi=10.1111/j.1539-6924.2005.00694.x |pmid=16506977 |bibcode=2005RiskA..25.1483P |s2cid=25784074}}</ref> Social invisibility is one such factor. Heat-related deaths can occur indoors, for instance among elderly people living alone. In these cases it can be challenging to assign heat as a contributing factor.<ref>{{Cite journal |last=Ro |first=Christine |date=2022-09-01 |title=Can Japan really reach "zero deaths" from heat stroke? |url=https://www.bmj.com/content/378/bmj.o2107 |journal=BMJ |language=en |volume=378 |article-number=o2107 |doi=10.1136/bmj.o2107 |issn=1756-1833 |s2cid=251954370 |doi-access=free|url-access=subscription }}</ref>
 === Heat index for temperature and relative humidity ===
@@ Line 101: / Line 100: @@
 === Surface ozone (air pollution) ===
-{{Further|Ozone#Ozone air pollution|Ozone#Low level ozone in urban areas}}High temperatures also make the effects of [[ozone]] pollution in urban areas worse. This raises heat-related mortality during heat waves.<ref>{{Cite journal |last1=Diem |first1=Jeremy E. |last2=Stauber |first2=Christine E. |last3=Rothenberg |first3=Richard |date=2017-05-16 |editor-last=Añel |editor-first=Juan A. |title=Heat in the southeastern United States: Characteristics, trends, and potential health impact |journal=PLOS ONE |volume=12 |issue=5 |pages=e0177937 |bibcode=2017PLoSO..1277937D |doi=10.1371/journal.pone.0177937 |issn=1932-6203 |pmc=5433771 |pmid=28520817 |doi-access=free}}</ref> During heat waves in urban areas, ground level ozone pollution can be 20 percent higher than usual.<ref>{{Cite journal |last1=Hou |first1=Pei |last2=Wu |first2=Shiliang |date=July 2016 |title=Long-term Changes in Extreme Air Pollution Meteorology and the Implications for Air Quality |journal=Scientific Reports |volume=6 |issue=1 |pages=23792 |bibcode=2016NatSR...623792H |doi=10.1038/srep23792 |issn=2045-2322 |pmc=4815017 |pmid=27029386}}</ref>
+{{Further|Ozone#Ozone air pollution|Ozone#Low level ozone in urban areas}}High temperatures also make the effects of [[ozone]] pollution in urban areas worse. This raises heat-related mortality during heat waves.<ref>{{Cite journal |last1=Diem |first1=Jeremy E. |last2=Stauber |first2=Christine E. |last3=Rothenberg |first3=Richard |date=2017-05-16 |editor-last=Añel |editor-first=Juan A. |title=Heat in the southeastern United States: Characteristics, trends, and potential health impact |journal=PLOS ONE |volume=12 |issue=5 |article-number=e0177937 |bibcode=2017PLoSO..1277937D |doi=10.1371/journal.pone.0177937 |issn=1932-6203 |pmc=5433771 |pmid=28520817 |doi-access=free}}</ref> During heat waves in urban areas, ground level ozone pollution can be 20 percent higher than usual.<ref>{{Cite journal |last1=Hou |first1=Pei |last2=Wu |first2=Shiliang |date=July 2016 |title=Long-term Changes in Extreme Air Pollution Meteorology and the Implications for Air Quality |journal=Scientific Reports |volume=6 |issue=1 |article-number=23792 |bibcode=2016NatSR...623792H |doi=10.1038/srep23792 |issn=2045-2322 |pmc=4815017 |pmid=27029386}}</ref>
 One study looked at fine particle concentrations and ozone concentrations from 1860 to 2000. It found that the global population-weighted fine particle concentrations increased by 5 percent due to climate change. Near-surface ozone concentrations rose by 2 percent.<ref>{{Cite journal |last1=Orru |first1=H. |last2=Ebi |first2=K. L. |last3=Forsberg |first3=B. |date=2017 |title=The Interplay of Climate Change and Air Pollution on Health |journal=Current Environmental Health Reports |volume=4 |issue=4 |pages=504–513 |doi=10.1007/s40572-017-0168-6 |issn=2196-5412 |pmc=5676805 |pmid=29080073|bibcode=2017CEHR....4..504O }}</ref>
@@ Line 111: / Line 110: @@
 === Reduced economic outputs ===
 [[File:09 Aus heatwave map.PNG|thumb|right|2009 southeastern Australia heat wave, thermal map approximate affected area shown in red]]
-Calculations from 2022 suggest that heat waves will shrink the global economy by about 1 percent decrease by the middle of the 21st century.<ref>{{Cite web |last=Benedek |first=Réfi |date=2022-07-12 |title=The cost of heatwaves |url=https://hypeandhyper.com/en/the-cost-of-heatwaves/ |access-date=2022-07-15 |publisher=HYPEANDHYPER }}</ref><ref>{{Cite magazine |title=Rising Heat is Making it Harder to Work in the U.S. — the Costs for the Economy Will Soar with Climate Change |url=https://time.com/6093845/how-heat-hurts-the-economy/ |magazine=Time |access-date=2022-07-15}}</ref><ref name=":4"/>
+Calculations from 2022 suggest that heat waves will shrink the global economy by about 1 percent decrease by the middle of the 21st century.<ref>{{Cite web |last=Benedek |first=Réfi |date=2022-07-12 |title=The cost of heatwaves |url=https://hypeandhyper.com/en/the-cost-of-heatwaves/ |access-date=2022-07-15 |publisher=HYPEANDHYPER }}</ref><ref>{{Cite magazine |title=Rising Heat is Making it Harder to Work in the U.S. — the Costs for the Economy Will Soar with Climate Change |url=https://time.com/6093845/how-heat-hurts-the-economy/ |magazine=Time |access-date=2022-07-15 |archive-date=15 July 2022 |archive-url=https://web.archive.org/web/20220715185031/https://time.com/6093845/how-heat-hurts-the-economy/ }}</ref><ref name=":4"/>
-Heat waves often have complex effects on economies. They reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure that is not suitable for extreme heat.<ref name=":3" /><ref name=":4" /> In 2016, a marine heatwave in Chile and its subsequent [[harmful algal bloom]] caused $800 million (USD) in export losses for the aquaculture industry as salmon and shellfish died off.<ref>{{Cite journal |last1=Trainer |first1=Vera L. |last2=Moore |first2=Stephanie K. |last3=Hallegraeff |first3=Gustaaf |last4=Kudela |first4=Raphael M. |last5=Clement |first5=Alejandro |last6=Mardones |first6=Jorge I. |last7=Cochlan |first7=William P. |date=2020-01-01 |title=Pelagic harmful algal blooms and climate change: Lessons from nature's experiments with extremes |journal=Harmful Algae |series=Climate change and harmful algal blooms |volume=91 |pages=101591 |doi=10.1016/j.hal.2019.03.009 |issn=1568-9883|doi-access=free |pmid=32057339 |bibcode=2020HAlga..9101591T }}</ref>
+Heat waves often have complex effects on economies. They reduce labour productivity, disrupt agricultural and industrial processes and damage infrastructure that is not suitable for extreme heat.<ref name=":3" /><ref name=":4" /> In 2016, a marine heatwave in Chile and its subsequent [[harmful algal bloom]] caused $800 million (USD) in export losses for the aquaculture industry as salmon and shellfish died off.<ref>{{Cite journal |last1=Trainer |first1=Vera L. |last2=Moore |first2=Stephanie K. |last3=Hallegraeff |first3=Gustaaf |last4=Kudela |first4=Raphael M. |last5=Clement |first5=Alejandro |last6=Mardones |first6=Jorge I. |last7=Cochlan |first7=William P. |date=2020-01-01 |title=Pelagic harmful algal blooms and climate change: Lessons from nature's experiments with extremes |journal=Harmful Algae |series=Climate change and harmful algal blooms |volume=91 |article-number=101591 |doi=10.1016/j.hal.2019.03.009 |issn=1568-9883|doi-access=free |pmid=32057339 |bibcode=2020HAlga..9101591T }}</ref>
 === Reduced agricultural outputs ===
@@ Line 136: / Line 135: @@
 === Floods ===
-Heat waves can also contribute to flooding. Because hot air is able to carry more moisture, heatwaves may be followed by extreme rainfall especially in [[Middle latitudes|mid-latitude]] regions.<ref>{{Cite journal |last1=Sauter |first1=Christoph |last2=Fowler |first2=Hayley J. |last3=Westra |first3=Seth |last4=Ali |first4=Haider |last5=Peleg |first5=Nadav |last6=White |first6=Christopher J. |date=2023-06-01 |title=Compound extreme hourly rainfall preconditioned by heatwaves most likely in the mid-latitudes |url=https://www.sciencedirect.com/science/article/pii/S2212094723000166 |journal=Weather and Climate Extremes |volume=40 |pages=100563 |doi=10.1016/j.wace.2023.100563 |bibcode=2023WCE....4000563S |issn=2212-0947|doi-access=free }}</ref> For example, the record-breaking heat wave that afflicted Pakistan beginning in May 2022 led to glacier melt and moisture flow. These were factors in the [[2022 Pakistan floods|devastating floods]] that began in June and claimed over 1,100 lives.<ref>{{Cite web |last1=Clarke |first1=Ben |last2=Otto |first2=Friederike |last3=Harrington |first3=Luke |title=Pakistan floods: what role did climate change play? |url=http://theconversation.com/pakistan-floods-what-role-did-climate-change-play-189833 |access-date=2022-09-04 |publisher=The Conversation |date=2 September 2022 }}</ref>
+Heat waves can also contribute to flooding. Because hot air is able to carry more moisture, heatwaves may be followed by extreme rainfall especially in [[Middle latitudes|mid-latitude]] regions.<ref>{{Cite journal |last1=Sauter |first1=Christoph |last2=Fowler |first2=Hayley J. |last3=Westra |first3=Seth |last4=Ali |first4=Haider |last5=Peleg |first5=Nadav |last6=White |first6=Christopher J. |date=2023-06-01 |title=Compound extreme hourly rainfall preconditioned by heatwaves most likely in the mid-latitudes |journal=Weather and Climate Extremes |volume=40 |article-number=100563 |doi=10.1016/j.wace.2023.100563 |bibcode=2023WCE....4000563S |issn=2212-0947|doi-access=free }}</ref> For example, the record-breaking heat wave that afflicted Pakistan beginning in May 2022 led to glacier melt and moisture flow. These were factors in the [[2022 Pakistan floods|devastating floods]] that began in June and claimed over 1,100 lives.<ref>{{Cite web |last1=Clarke |first1=Ben |last2=Otto |first2=Friederike |last3=Harrington |first3=Luke |title=Pakistan floods: what role did climate change play? |url=http://theconversation.com/pakistan-floods-what-role-did-climate-change-play-189833 |access-date=2022-09-04 |publisher=The Conversation |date=2 September 2022 }}</ref>
 === Wild animals on land ===
@@ Line 144: / Line 143: @@
 ===Oceans===
-[[Marine heatwave]]s may cause mass mortality in fish populations, especially for species that are better adapted to cooler temperatures.<ref name=":03">{{Cite journal |last1=Smith |first1=Kathryn E. |last2=Burrows |first2=Michael T. |last3=Hobday |first3=Alistair J. |last4=King |first4=Nathan G. |last5=Moore |first5=Pippa J. |last6=Sen Gupta |first6=Alex |last7=Thomsen |first7=Mads S. |last8=Wernberg |first8=Thomas |last9=Smale |first9=Dan A. |date=2023-01-16 |title=Biological Impacts of Marine Heatwaves |url=https://www.annualreviews.org/doi/10.1146/annurev-marine-032122-121437 |journal=Annual Review of Marine Science |language=en |volume=15 |issue=1 |pages=119–145 |doi=10.1146/annurev-marine-032122-121437 |bibcode=2023ARMS...15..119S |issn=1941-1405|hdl=11250/3095845 |hdl-access=free }}</ref> Species that have adapted to warmer temperatures may expand their range during a heatwave. These invasive species may outcompete the native species that experience higher mortality during a heatwave, which disrupts ecosystem functioning.<ref name=":03" /> Marine heatwaves have also been correlated with negative impacts on [[foundation species]] such as coral and kelp.<ref>{{Cite journal |last1=Smale |first1=Dan A. |last2=Wernberg |first2=Thomas |last3=Oliver |first3=Eric C. J. |last4=Thomsen |first4=Mads |last5=Harvey |first5=Ben P. |last6=Straub |first6=Sandra C. |last7=Burrows |first7=Michael T. |last8=Alexander |first8=Lisa V. |last9=Benthuysen |first9=Jessica A. |last10=Donat |first10=Markus G. |last11=Feng |first11=Ming |last12=Hobday |first12=Alistair J. |last13=Holbrook |first13=Neil J. |last14=Perkins-Kirkpatrick |first14=Sarah E. |last15=Scannell |first15=Hillary A. |date=April 2019 |title=Marine heatwaves threaten global biodiversity and the provision of ecosystem services |url=https://www.nature.com/articles/s41558-019-0412-1 |journal=Nature Climate Change |language=en |volume=9 |issue=4 |pages=306–312 |doi=10.1038/s41558-019-0412-1 |bibcode=2019NatCC...9..306S |issn=1758-6798|hdl=2160/3a9b534b-03ab-4619-9637-2ab06054fe70 |hdl-access=free }}</ref>
+[[Marine heatwave]]s may cause mass mortality in fish populations, especially for species that are better adapted to cooler temperatures.<ref name=":03">{{Cite journal |last1=Smith |first1=Kathryn E. |last2=Burrows |first2=Michael T. |last3=Hobday |first3=Alistair J. |last4=King |first4=Nathan G. |last5=Moore |first5=Pippa J. |last6=Sen Gupta |first6=Alex |last7=Thomsen |first7=Mads S. |last8=Wernberg |first8=Thomas |last9=Smale |first9=Dan A. |date=2023-01-16 |title=Biological Impacts of Marine Heatwaves |url=https://www.annualreviews.org/doi/10.1146/annurev-marine-032122-121437 |journal=Annual Review of Marine Science |language=en |volume=15 |issue=1 |pages=119–145 |doi=10.1146/annurev-marine-032122-121437 |bibcode=2023ARMS...15..119S |issn=1941-1405|hdl=11250/3095845 |hdl-access=free }}</ref> Species that have adapted to warmer temperatures may expand their range during a heatwave. These invasive species may outcompete the native species that experience higher mortality during a heatwave, which disrupts ecosystem functioning.<ref name=":03" /> Marine heatwaves have also been correlated with negative impacts on [[foundation species]] such as coral and kelp.<ref>{{Cite journal |last1=Smale |first1=Dan A. |last2=Wernberg |first2=Thomas |last3=Oliver |first3=Eric C. J. |last4=Thomsen |first4=Mads |last5=Harvey |first5=Ben P. |last6=Straub |first6=Sandra C. |last7=Burrows |first7=Michael T. |last8=Alexander |first8=Lisa V. |last9=Benthuysen |first9=Jessica A. |last10=Donat |first10=Markus G. |last11=Feng |first11=Ming |last12=Hobday |first12=Alistair J. |last13=Holbrook |first13=Neil J. |last14=Perkins-Kirkpatrick |first14=Sarah E. |last15=Scannell |first15=Hillary A. |date=April 2019 |title=Marine heatwaves threaten global biodiversity and the provision of ecosystem services |url=https://www.nature.com/articles/s41558-019-0412-1 |journal=Nature Climate Change |language=en |volume=9 |issue=4 |pages=306–312 |doi=10.1038/s41558-019-0412-1 |bibcode=2019NatCC...9..306S |issn=1758-6798|hdl=2160/3a9b534b-03ab-4619-9637-2ab06054fe70 |hdl-access=free |url-access=subscription }}</ref>
 == Options for reducing impacts on humans ==
 A possible public health measure during heat waves is to set up air-conditioned public cooling centres. Adding air conditioning in schools provides a cooler work place.<ref name="chicago">{{Cite news |last=Kaufman |first=Leslie |date=2011-05-23 |title=A City Prepares for a Warm Long-Term Forecast |url=https://www.nytimes.com/2011/05/23/science/earth/23adaptation.html |access-date=2023-02-08 |work=The New York Times |issn=0362-4331}}</ref> But it can result in additional [[greenhouse gas emissions]] unless [[solar energy]] is used.
-Policymakers, funders and researchers have created the [[Extreme Heat Resiliance Alliance|Extreme Heat Resilience Alliance]] coalition under the [[Atlantic Council]]. This advocates for naming heat waves, measuring them, and ranking them to build better awareness of their impacts.<ref>{{Cite web |title=Extreme Heat Resilience Alliance: Reducing Extreme Heat Risk for Vulnerable People |url=https://wcr.ethz.ch/news-and-events/EHRA.html |url-status=dead |archive-url=https://web.archive.org/web/20200821212642/https://wcr.ethz.ch/news-and-events/EHRA.html |archive-date=21 August 2020 |access-date=2020-09-02 |publisher=wcr.ethz.ch}}</ref><ref>{{Cite web |title=The world's getting hotter. Can naming heat waves raise awareness of the risks? |date=19 August 2020 |url=https://www.pri.org/stories/2020-08-19/world-s-getting-hotter-can-naming-heat-waves-raise-awareness-risks |access-date=2020-09-02 |publisher=The World from PRX}}</ref>
+Policymakers, funders and researchers have created the [[Extreme Heat Resiliance Alliance|Extreme Heat Resilience Alliance]] coalition under the [[Atlantic Council]]. This advocates for naming heat waves, measuring them, and ranking them to build better awareness of their impacts.<ref>{{Cite web |title=Extreme Heat Resilience Alliance: Reducing Extreme Heat Risk for Vulnerable People |url=https://wcr.ethz.ch/news-and-events/EHRA.html |archive-url=https://web.archive.org/web/20200821212642/https://wcr.ethz.ch/news-and-events/EHRA.html |archive-date=21 August 2020 |access-date=2020-09-02 |publisher=wcr.ethz.ch}}</ref><ref>{{Cite web |title=The world's getting hotter. Can naming heat waves raise awareness of the risks? |date=19 August 2020 |url=https://www.pri.org/stories/2020-08-19/world-s-getting-hotter-can-naming-heat-waves-raise-awareness-risks |access-date=2020-09-02 |publisher=The World from PRX}}</ref>
 == Recent examples by country or region ==
@@ Line 164: / Line 163: @@
 === China ===
-A study found the average resident in China was exposed to 16 days of heat waves in 2023, with more than 37,000 heat wave-related deaths. Besides, the number of work hours lost due to heat stress in China was 36.9 billion in 2023, and China’s citizens experienced a 60% surge in lost safe outdoor activity hours, with each person losing 2.2 hours on average each day. The study predicted that by the 2060s, annual heat wave-related mortality is expected to reach 29,000 to 38,000 in China, with a 28% to 37% increase in work hours lost.<ref>{{cite web|author=Ding Rui|work=[[Sixth Tone]]|url=https://www.sixthtone.com/news/1016149|title=Heat Wave-Related Deaths Soared in China in 2023, Report Finds|date=November 7, 2024}}</ref>
+A study found the average resident in China was exposed to 16 days of heat waves in 2023, with more than 37,000 heat wave-related deaths. Besides, the number of work hours lost due to heat stress in China was 36.9 billion in 2023, and China's citizens experienced a 60% surge in lost safe outdoor activity hours, with each person losing 2.2 hours on average each day. The study predicted that by the 2060s, annual heat wave-related mortality is expected to reach 29,000 to 38,000 in China, with a 28% to 37% increase in work hours lost.<ref>{{cite web|author=Ding Rui|work=[[Sixth Tone]]|url=https://www.sixthtone.com/news/1016149|title=Heat Wave-Related Deaths Soared in China in 2023, Report Finds|date=November 7, 2024}}</ref>
 === United States ===
 {{ multiple image | total_width=450
-| image1 = 1960- Heat wave indicators - US.svg |caption1= US heat waves have increased in frequency, average duration, and intensity.<ref name=EPA_202406/> <br><br>Also, heat wave ''seasons'' have grown in length.<ref name=EPA_202406>{{cite web |title=Climate Change Indicators: Heat Waves |url=https://www.epa.gov/climate-indicators/climate-change-indicators-heat-waves |publisher=U.S. Environmental Protection Agency (EPA) |archive-url=https://web.archive.org/web/20241007114317/https://www.epa.gov/climate-indicators/climate-change-indicators-heat-waves |archive-date=7 October 2024 |date=June 2024 |url-status=live }} EPA cites data source: NOAA, 2024.</ref>
+| image1 = 1960- Heat wave indicators - US.svg |caption1= US heat waves have increased in frequency, average duration, and intensity.<ref name=EPA_202406/> <br /><br />Also, heat wave ''seasons'' have grown in length.<ref name=EPA_202406>{{cite web |title=Climate Change Indicators: Heat Waves |url=https://www.epa.gov/climate-indicators/climate-change-indicators-heat-waves |publisher=U.S. Environmental Protection Agency (EPA) |archive-url=https://web.archive.org/web/20241007114317/https://www.epa.gov/climate-indicators/climate-change-indicators-heat-waves |archive-date=7 October 2024 |date=June 2024 |url-status=live }} EPA cites data source: NOAA, 2024.</ref>
 | image2 = 1960- Annual average number of days spent in heat waves - US.svg |caption2= Over decades, the average number of days spent in heat waves in the U.S. annually has increased, based on increases in both the average annual number of heat waves and on their average durations.<ref name=EPA_202406/>
 }}
@@ Line 175: / Line 174: @@
 According to a 2022 study, 107 million people in the US will experience extremely dangerous heat in the year 2053.<ref>{{Cite web |last1=Miller |first1=Brandon |last2=Waldrop |first2=Theresa |date=2022-08-16 |title=An 'extreme heat belt' will impact over 100 million Americans in the next 30 years, study finds |url=https://www.cnn.com/2022/08/15/weather/extreme-heat-belt-us-impact-study-climate/index.html |access-date=2022-08-22 |publisher=CNN}}</ref>
-Heat waves are the most lethal type of weather phenomenon in the United States. Between 1992 and 2001, deaths from excessive heat in the United States numbered 2,190, compared with 880 deaths from floods and 150 from [[tropical cyclone]]s.<ref>{{cite web |title=Hot Weather Tips and the Chicago Heat Plan |url=http://chicago.about.com/library/blank/bl_hot_weather_tips.htm |url-status=dead |archive-url=https://web.archive.org/web/20060621110942/http://chicago.about.com/library/blank/bl_hot_weather_tips.htm |archive-date=21 June 2006 |access-date=27 July 2006 |work=About.com}}</ref> About 400 deaths a year on average are directly due to heat in the United States.<ref name="heat epidemiology" /> The [[1995 Chicago heat wave]], one of the worst in US history, led to approximately 739 heat-related deaths over 5 days.<ref>''[http://www.annals.org/cgi/content/abstract/129/3/173 Near-Fatal Heat Stroke during the 1995 Heat Wave in Chicago]''. ''Annals of Internal Medicine'' Vol. 129 Issue 3</ref> In the United States, the loss of human life in hot spells in summer exceeds that caused by all other weather events. These include [[lightning]], [[rainstorm|rain]], [[flood]]s, [[hurricane]]s, and [[tornado]]es.<ref name="Klinenberg">{{cite book |last=Klinenberg |first=Eric |title=Heat Wave: A Social Autopsy of Disaster in Chicago |publisher=Chicago University Press |year=2002 |isbn=9780226443218}}</ref><ref name="slate">''[http://slate.com/id/2068612/ Dead Heat: Why don't Americans sweat over heat-wave deaths?]'' By Eric Klinenberg. Slate.com. Posted Tuesday, 30 July 2002</ref>
+Heat waves are the most lethal type of weather phenomenon in the United States. Between 1992 and 2001, deaths from excessive heat in the United States numbered 2,190, compared with 880 deaths from floods and 150 from [[tropical cyclone]]s.<ref>{{cite web |title=Hot Weather Tips and the Chicago Heat Plan |url=http://chicago.about.com/library/blank/bl_hot_weather_tips.htm |archive-url=https://web.archive.org/web/20060621110942/http://chicago.about.com/library/blank/bl_hot_weather_tips.htm |archive-date=21 June 2006 |access-date=27 July 2006 |work=About.com}}</ref> About 400 deaths a year on average are directly due to heat in the United States.<ref name="heat epidemiology" /> The [[1995 Chicago heat wave]], one of the worst in US history, led to approximately 739 heat-related deaths over 5 days.<ref>''[http://www.annals.org/cgi/content/abstract/129/3/173 Near-Fatal Heat Stroke during the 1995 Heat Wave in Chicago]''. ''Annals of Internal Medicine'' Vol. 129 Issue 3</ref> In the United States, the loss of human life in hot spells in summer exceeds that caused by all other weather events. These include [[lightning]], [[rainstorm|rain]], [[flood]]s, [[hurricane]]s, and [[tornado]]es.<ref name="Klinenberg">{{cite book |last=Klinenberg |first=Eric |title=Heat Wave: A Social Autopsy of Disaster in Chicago |publisher=Chicago University Press |year=2002 |isbn=978-0-226-44321-8}}</ref><ref name="slate">''[http://slate.com/id/2068612/ Dead Heat: Why don't Americans sweat over heat-wave deaths?]'' By Eric Klinenberg. Slate.com. Posted Tuesday, 30 July 2002</ref>
 About 6,200 Americans need hospital treatment each summer, according to data from 2008. This is due to excessive heat, and those at highest risk are poor, uninsured or elderly.<ref>[http://newswise.com/articles/view/542519/ Most People Struck Down by Summer Heat Are Poor] Newswise, Retrieved on 9 July 2008.</ref>

Heat wave: Difference between revisions

Latest revision as of 02:16, 18 December 2025

Contents

Definitions

Definitions by country

Europe

North America

Oceania

Marine Heatwaves

Observations

Causes

Climate change

Impacts on human health

Heat-related health effects for vulnerable humans

Mortality

Underreporting of fatalities

Heat index for temperature and relative humidity

Psychological and sociological effects

Surface ozone (air pollution)

Impacts on societies

Reduced economic outputs

Reduced agricultural outputs

Farmed animals

Infrastructural damage

Power outages

Impacts on the environment

Wildfires

Floods

Wild animals on land

Oceans

Options for reducing impacts on humans

Recent examples by country or region

Around the world in 2024

India

Southeast Asia

China

United States

See also

References

Navigation menu

Heat wave: Difference between revisions

Latest revision as of 02:16, 18 December 2025

Definitions

Definitions by country

Europe

North America

Oceania

Marine Heatwaves

Observations

Causes

Climate change

Impacts on human health

Heat-related health effects for vulnerable humans

Mortality

Underreporting of fatalities

Heat index for temperature and relative humidity

Psychological and sociological effects

Surface ozone (air pollution)

Impacts on societies

Reduced economic outputs

Reduced agricultural outputs

Farmed animals

Infrastructural damage

Power outages

Impacts on the environment

Wildfires

Floods

Wild animals on land

Oceans

Options for reducing impacts on humans

Recent examples by country or region

Around the world in 2024

India

Southeast Asia

China

United States

See also

References

Navigation menu

Search