(CNN Spanish) — Argentina crosses the eighth heat wave since the beginning of the austral summer, a figure that almost doubles what is usual for the country. How is it explained?
There is a key factor that is fueling the oppressive temperatures: the high pressures in the Atlantic Ocean near the Patagonian coast, south of the province of Buenos Aires, he explained to CNN en Español Cyndi Fernandez, of the National Meteorological Service of Argentina (SMN). “What that position in that place is doing is favoring a predominance, throughout the entire summer, of winds from the north sector almost without interruptions,” he said.
In addition to the warm air that arrives continuously, “there is almost no entry of cold air,” Fernández specified, resulting in an exceptionally hot summer: in Buenos Aires, for example, the highest temperature for a month of February was recorded in more than 60 years old.
How does climate change affect?
Climate change as a result of human action intensifies extreme weather events, including heat waves —which are defined as periods in which minimum and maximum temperatures exceed, for at least three consecutive days, certain values that depend on the location— , scientific studies have verified.
(According to a key report by the UN Intergovernmental Panel on Climate Change published in 2021, for example, extreme heat waves are already about five times more likely to occur from rising temperatures from greenhouse emissions). greenhouse gases).
However, in order to attribute these heat waves —particularly in Argentina— to climate change, it is necessary to carry out an attribution study, Fernández explained, investigations that are carried out once the episodes end and that take longer.
Therefore, at this stage, what can be stated is that it is known that climate change impacts heat waves, but that a specific analysis of the case is necessary to establish a direct attribution.
A key number: 60
An attribution study made it possible to establish, for example, that the heat wave that hit Argentina at the beginning of December last year —with temperatures that exceeded 40º Celsius in 24 meteorological stations in the country— was 60 times more likely due to climate changeaccording to the World Weather Attribution
To quantify the effect of climate change in the north of the country, the specialists then studied “meteorological data and model simulations to compare the current climate, 1.2 °C warmer than in 1850, with the climate of the past,” explains the SMN.
In addition to being 60 times more likely to occur, the analysis showed that it made it 1.4 degrees Celsius hotter.
The researchers determined that a similar event could be expected to occur once every 20 years, something that would have been “extremely unusual” without the consequences of planet-warming greenhouse gas emissions.
Horizonte 2050
The prospects for the medium term in South America are not encouraging.
Magazine Nature published in 2019 an investigation that allows anticipating how the region will be affected, according to two emission scenarios of greenhouse gases established by the Intergovernmental Panel of Experts on Climate Change.
In the more moderate of the two scenarios, the percentage of days of extreme heat is expected to increase between five and 10 times in northern South America and the Atacama desert, and the number of heat wave days per season is expected to increase by less than from three in the period 1961-1990 to between 15 and 30 between 2045 and 2055.
In the south of the region, the projection is more moderate. In Patagonia, for example, it is expected that the days of extreme heat in summer will rise from 5% to close to 10% in the periods mentioned above and the days of heat waves will reach five.
In the most pessimistic emissions scenario, the situation becomes much more drastic. By the end of the century, according to the study, the percentage of extremely hot days could reach 100% in the north of the region and more than 80% in the Atacama desert.
Heat waves and daily temperature records will strongly affect large tropical cities, according to the study.