The aridification It advances relentlessly in most of the planet. More than three quarters of the world (77.6%) have experienced drier conditions between 1990-2020 than in the previous thirty years. And lands classified as arid have expanded by 4.3 million km2, equivalent to half the size of Australia. Behind it is the global increase in temperatures, as certified for the first time by a scientific organization associated with the UN, which assures that the report published this Monday is a “turning point.”
«This analysis finally dispels uncertainty that has long surrounded global drought trends,” says Ibrahim Thiaw, executive secretary of the United Nations Convention to Combat Desertification (UNCCD). “For the first time, the aridity crisis has been documented with scientific clarity, revealing an existential threat affecting billions of people around the world.”
In reality, much of the planet has, by nature, many arid areas. The problem is that they are increasing and, those that exist, are getting worse. “There is a trend related to climate change to an increase in both arid conditions and the extension of arid zones,” explains Enrique Morán-Tejeda, professor of Climatology at the University of the Balearic Islands and main author of the report.
Challenges
For years, documenting increasing aridity has been a challenge. The long-term nature of aridity in the face of drought made it complicated. Also the measurement of the parameters that determine aridification, which not only depends on precipitation but also on evaporation and transpiration of plants. While droughts end after months or even years, allowing some recovery, the same does not occur with aridity. A territory that becomes arid will no longer be able to return to its previous conditions. «Aridity represents a permanent and relentless transformation» says Thiaw.
The report highlights that there are regions that were not classified as arid, some with subhumid climates, whose conditions have changed to become arid zones. Some areas have experienced wetter conditions, but they are in the minority: just 22.4%.
«The general trend is clear: the drylands are expanding, which causes ecosystems and societies to suffer the life-threatening impacts of aridity,” says the note distributed by the UN.
Affected population
The tendency towards aridity has been “particularly prevalent” in Europethe western United States, Brazil, Asia and central Africa, the report says. It affected almost all of Europe (95.9 percent). “All these areas tend to be more arid and in the future the forecasts indicate that it will become even more so,” explains Morán-Tejeda.
That is, today a quarter of the world’s population (2.3 billion people) lives in the planet’s expanding drylands. And aridity projections suggest that up to 5 billion people could inhabit dry lands by the end of the century if the worst climate change projections come true.
Scientists advocate starting a adaptation. «In Spain we are used to living with drought. But since aridity is more long-term, people do not have the same perception of risk,” explains Morán-Tejeda. “However, the impacts it has on agricultural production, the economy (…), are impacts that are very structural,” he says.
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