The assessment method used by the University of Bristol team is based on local temperature variability, not absolute values. Better understanding of the potential impact on the population
Heat waves kill hundreds every year
(Sustainabilityenvironment.com) – The summer of 2003 in Europe was hot. An unprecedented heat waves that shattered the temperature records in many countries (in Portugal they touched the 49 and C) and – it is estimated – made a little less than 40,000 deaths, of which almost half in Italy. But however powerful, this heat wave is not among the most intense recorded globally. This is stated by a new study that recalculated the intensity and impact of these extreme phenomena.
Unlike usual, the work is not based on absolute temperature extremes, but on excess heat with respect to local temperature variability. With this model, the first three hottest events ever occurred in South-East Asia in April 1998 (reached 32.8 ºF, an important anomaly for the period), in Brazil in November 1985 (with a peak of 36.5 ºF), and in the southern United States in July 1980, when temperatures rose to 38.4 ºC.
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The heat wave that hit the Pacific North-West last summer, between Washington and the Canadian province of British Columbia, is also out of the top 3. Although the temperature had risen to 49.6 ºC in locations like Lytton, almost 5 degrees higher than the previous absolute record.
“The western North America heat wave will be remembered because of its widespread devastation. 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“, explains Vikki Thompson of Bristol University and the first author of the study.
“It is important to assess the severity of heat waves in terms of local temperature variability because both humans and the natural ecosystem will adapt to this, so in regions where there is less variation, a smaller absolute extreme may have more harmful effects“, concludes Thompson.
