`Study: Decades of Heatwaves Have Gone Unreported - Olive Oil Times

Study: Decades of Heatwaves Have Gone Unreported

May. 25, 2022
Paolo DeAndreis

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Heatwaves are increas­ingly affect­ing pop­u­la­tion and crops around the globe.

However, new research indi­cates that the impacts of some of the worst heat­waves in recent decades have gone unre­ported since they hap­pened in coun­tries that lacked the means to keep track of such events.

Climate change is one of the great­est global health prob­lems of our time, and we have shown that many heat­waves out­side of the devel­oped world have gone largely unno­ticed.- Dann Mitchell, cli­mate sci­ence pro­fes­sor, University of Bristol

In a new study pub­lished in Science Advances, researchers from the University of Bristol and other aca­d­e­mic insti­tu­tions noted how the extreme June 2021 North American heat­wave might be used as a ref­er­ence to bet­ter eval­u­ate the phe­nom­ena hap­pen­ing in other parts of the world.

While it is clear that the event was extreme, it is not obvi­ous whether other areas in the world have also expe­ri­enced events so far out­side their nat­ural vari­abil­ity,” the study authors wrote.

See Also:NASA Climate Scientist Wins World Food Prize

Last sum­mer’s North America heat­wave broke sev­eral tem­per­a­ture records, includ­ing the all-time Canadian high of 49.6 °C in Lytton, British Columbia, on June 29, 4.6 °C hot­ter than the pre­vi­ous record.

In its press release, the University of Bristol empha­sized how the paper ana­lyzed the most intense heat­waves around the world not­ing how some of these went almost unno­ticed decades ago.”


The researchers found that the west­ern North America heat wave is indeed remark­able as only five other heat­waves were found to be more extreme since 1960.

We find that in both re-analy­ses and cli­mate pro­jec­tions, the sta­tis­ti­cal dis­tri­b­u­tion of extremes increases through time, in line with the dis­tri­b­u­tion mean shift due to cli­mate change,” the sci­en­tists wrote. Regions that, by chance, have not had a recent extreme heat­wave may be less pre­pared for poten­tially immi­nent events.”

More specif­i­cally, the study, which cal­cu­lated how extreme heat­waves were rel­a­tive to the local tem­per­a­ture, showed the top three hottest-ever in the respec­tive regions were in Southeast Asia in April 1998, which hit 32.8 °C, Brazil in November 1985, peak­ing at 36.5 °C, and the south­ern U.S. in July 1980, when tem­per­a­tures rose to 38.4 °C.

The west­ern North America heat­wave will be remem­bered because of its wide­spread dev­as­ta­tion,” said Vikki Thompson, a researcher at the Cabot Institute for the Environment of the University of Bristol.“However, the study exposes sev­eral greater mete­o­ro­log­i­cal extremes in recent decades, some of which went largely under the radar likely due to their occur­rence in more deprived coun­tries.”

It is impor­tant to assess the sever­ity of heat­waves in terms of local tem­per­a­ture vari­abil­ity because both humans and the nat­ural eco-sys­tem will adapt to this, so in regions where there is less vari­a­tion, a smaller absolute extreme may have more harm­ful effects,” she added.

According to researchers, heat extremes are a nat­ural part of the cli­mate sys­tem but are becom­ing hot­ter and longer in dura­tion because of anthro­pogenic cli­mate change.

The sci­en­tists warned that such extremes rep­re­sent a threat to human health and ecol­ogy as their fre­quency is grow­ing in many regions through­out the globe.

Excess mor­tal­ity due to extreme heat is well doc­u­mented, with an aver­age of six heat-related deaths per 100,000 res­i­dents each year in North America esti­mated for 2000 to 2019,” the sci­en­tists wrote. Heat impacts are mag­ni­fied in cities, and with nearly 70 per­cent of the world’s pop­u­la­tion expected to live in cities by 2050, the risks posed by extreme heat events will also increase.”

See Also:2021 Was Earth’s Fifth Hottest Year, Scientists Say

Recent stud­ies con­firm that heat­waves are occur­ing more fre­quently than in the past and are last­ing longer. A recent BBC report found that the num­ber of days with tem­per­a­tures higher than 50 °C has almost dou­bled in the last 40 years.

The cur­rent heat­wave hit­ting India and Pakistan is tak­ing its toll on the pop­u­la­tion, as dozens of cit­i­zens of both coun­tries died because of the extreme and pro­longed heat.

Local author­i­ties believe that the heat­wave began seven or eight weeks ago. According to the Indian Meteorological Department, cited by Inside Climate News, March was the hottest recorded month since 1961 in Pakistan.

In north­west and cen­tral India, the aver­age max­i­mum tem­per­a­ture through­out April was the high­est in over a cen­tury.

Heatwaves also take a toll on crop vital­ity and agri­cul­tural out­put, includ­ing olives. Heatwaves have been cited fre­quently by pro­duc­ers in recent years as rea­sons why har­vests have been lower than expected.

In the 2021/22 crop year, local pro­duc­ers believe that Egypt’s olive out­put fell up to 80 per­cent because of the heat­waves. Similar wor­ries at the time were also cited by Sicilian and Moroccan grow­ers.

In the lat­est Chatham House report on cli­mate change, researchers cited how dev­as­tat­ing heat­waves are con­tribut­ing to a dras­tic reduc­tion of sta­ple crop yields.

According to the report, the dev­as­tat­ing heat­waves are now between 10 and 600 times more likely due to the chang­ing cli­mate. It is believed that at least 3.9 bil­lion peo­ple will be severely exposed to such heat­waves by 2040, result­ing in 10 mil­lion deaths each year from excess heat.

In ref­er­ence to the study, Dann Mitchell, a pro­fes­sor at the University of Bristol, said cli­mate change is one of the great­est global health prob­lems of our time, and we have shown that many heat­waves out­side of the devel­oped world have gone largely unno­ticed.”

The coun­try-level bur­den of heat on mor­tal­ity can be in the thou­sands of deaths, and coun­tries which expe­ri­ence tem­per­a­tures out­side their nor­mal range are the most sus­cep­ti­ble to these shocks,” he con­cluded.


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