How long will these records hold? The year 2023 should probably be the hottest ever observed in history, Copernicus, the European climate observatory, announced this week, after an almost uninterrupted series of heat records at all levels – local, national, regional – of the planet. Under the effect of greenhouse gas emissions produced by humans since the industrial era, the atmosphere is becoming increasingly warmer. Scientists assure it, these new levels will be exceeded. They could be even more quickly with the installation in the Pacific of El Niño, this natural phenomenon which has been added to global warming of human origin for several months and whose first effects are beginning to be felt.
In India, August was recorded as the hottest and driest month since records began more than a century ago. In the United States, the month of July saw heat records fall one after the other. Latin America also experienced winter heat waves: the thermometer happily exceeded 30°C in São Paulo, Brazil, it was close to 25°C in Santiago, Chile, very unusual temperatures for the season. “The heat waves observed in India and North America recently [pourraient être liées à El Niño]”, cautiously advances Davide Faranda, CNRS researcher at the climate and environmental sciences laboratory (LSCE) at Paris-Saclay University.
This is due to the rise in surface water temperature in the South Pacific, which has the effect of warming the atmosphere, increasing the average temperature of the globe and promoting extreme weather events. Appearing in June, this phenomenon will be reinforced during the autumn, to reach its climax at the end of the year. “For the moment, we cannot predict the intensity of El Niño at the end of the year, there are still atmospheric phenomena which will influence its severity,” specifies oceanographer Jérôme Vialard, from the Pierre-Simon-Laplace Institute (IPSL).
Serial consequences
Complex in terms of its meteorological implications and the extreme events it generates, the El Niño phenomenon remains difficult to define. But it could well offer us a glimpse of what our planet would be like with a few tenths of a degree of additional warming. Thus, last May, the World Meteorological Organization (WMO) estimated that it was 66% likely that the global average temperature would temporarily exceed the symbolic bar of 1.5°C of warming for at least one year between 2023 and 2027. That is, the threshold reference of the Paris agreement, signed in 2015, and which plans to contain global warming below this limit compared to the pre-industrial era. “This does not mean that in the next five years we will exceed the level of 1.5°C specified in the Paris agreement, because [celui-ci] refers to long-term warming, over many years. However, this is yet another wake-up call,” said WMO climate services manager Chris Hewitt.
Stifling heat, drought, unprecedented climate change: the terrible child of the Pacific projects us into a future where extreme events are both more recurrent and more intense. “El Niño provides us with a taste of the future climate, because, without its contribution to temporarily increasing global temperatures, we would rather observe these extremes in 2030-2040”, underlines Davide Faranda. The phenomenon has known regional consequences: increased rainfall in South America, drought in Australia, unprecedented heat wave in India.
The expected effects are not limited to the weather, they collide with other crises, such as that of the grain blockade in Ukraine, by disrupting the crop cycle in certain regions and the major balances of global food production. In June, the head of the Indian Central Bank testified to his “concern” on the subject of agriculture. Alarm shared by Thailand, which underlined the future impact on foodstuffs.
Psychological effect in Europe
By threatening harvests, El Niño causes the price of certain products to soar. Like cocoa, whose world prices reached around $3,500 a ton, compared to $2,400 a year ago. “Even if certain effects of El Niño are well known, we still do not know the implication and the location of these risks. This climatic variability causes great uncertainties on the markets”, explains economist Rémi Generoso, lecturer at the University of Lille and associate researcher at Paris-Nanterre. The decline in fish populations is already well documented: “In the eastern Pacific, El Niño stops the influx of cold water that brings nutrients to the entire food chain, causing a collapse of fish stocks. biomass in the region,” explains oceanographer Jérôme Vialard. Peru has thus anticipated a sharp decline in anchovy fishing, an essential sector for the supply of omega 3 to fish and animal farms on which the country is highly dependent.
Europe, despite recent heat waves, should escape the direct consequences of El Niño. “However, if we pass the 1.5°C mark, there could be a psychological impact,” predicts Jérôme Vialard. An awareness of the path that remains to be taken to try to limit global warming.