The scorching summer of 2022/23 in Argentina left its mark as one of the most extreme ever recorded, setting a new record of 10 heatwave events during the warm season. A recent scientific study by a group of researchers from the Complutense University of Madrid and the Spanish National Research Council analyses the synoptic and thermodynamic conditions of the four most extensive heatwaves, shedding light on the complex interaction of atmospheric phenomena.
The study, published in the leading scientific journal Communications Earth & Environment, uses ERA5 reanalysis data to investigate the atmospheric dynamics behind Argentina's exceptional summer and performs three attribution exercises to unravel the role of atmospheric circulation, drought and climate change in the recorded maximum temperatures. 

The summer of 2022/23 had a warm anomaly of 1.56°C in southern South America, the warmest in six decades. High temperatures in much of the country, particularly in the centre and north, exceeded several historical records. In addition, more than 40% of the warm season days in the central region of the country were classified as heatwave days. In addition, more than 60% of the days of the season experienced severe heat stress conditions, exceeding climatological expectations by 25%. These extreme conditions, exacerbated by the third consecutive year of La Niña conditions, led to record soil moisture deficits and high sensible heat fluxes in northern Argentina, coinciding with the areas affected by extreme temperatures.
Through meticulous synoptic and thermodynamic analyses, the researchers identified the role of mid-level anticyclonic anomalies in driving the heat waves. These atmospheric systems, characterised by clear skies and radiative heating, were found to be key drivers of the prolonged warm spells. Further analysis revealed that three heat waves were associated with quasi-stationary anticyclones and one with transient anticyclones. Furthermore, the study underlines the fundamental role of diabatic heating processes in driving daily temperature variations.

Beyond atmospheric dynamics, research is looking at the multiple effects of climate change and soil moisture deficits. Consecutive years of La Niña led to severe droughts, which amplified the intensity of heat waves through soil-atmosphere coupling mechanisms. An attribution exercise using analogue techniques quantified the contributions of atmospheric circulation, soil moisture and climate change. All were found to exacerbate temperature anomalies. In particular, climate change was found to have increased the intensity of heat waves by +0.5 to +1.2°C compared to previous decades (1951-1980).
Looking ahead, the study raises concerns about the future recurrence of such extreme summers. With climate change expected to increase the frequency of La Niña events and accentuate temperature trends, the likelihood of a recurrence of extreme summers is high. The research highlights the urgency of taking proactive measures to mitigate the impact of future heatwaves on critical sectors such as health, energy and agriculture.