Quarter of land will be drier under 2°C warming: study

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But if we contain average warming to 1.5°C (2.7°F), this will be limited to about a tenth - sparing two-thirds of the land projected to parch under 2°C, they concluded in a study published in Nature Climate Change.

At 1.5°C, parts of southern Europe, southern Africa, central America, coastal Australia and Southeast Asia - areas home to more than a fifth of humanity - "would avoid significant aridification" predicted under 2°C, said study co-author Su-Jong Jeong of the Southern University of Science and Technology in Shenzhen, China.

"Accomplishing 1.5°C would be a meaningful action for reducing the likelihood of aridification and related impacts," he told AFP.

Jeong and a team used projections from several climate models, under different warming scenarios, to predict land drying patterns.

Aridification is a major threat, hastening land degradation and desertification, and the loss of plants and trees crucial for absorbing Earth-warming carbon dioxide.

It also boosts droughts and wildfires, and affects water quality for farming and drinking.

The team found that at 2°C, which could arrive any time between 2052 and 2070, between 24% and 32% of the total land surface will become drier.

This includes land in all five climate categories today - hyper-arid, arid, semi-arid, dry sub-humid, and humid.

But at 1.5°C - the lower, aspirational limit also written into the climate-rescue Paris Agreement - this is reduced to between eight and 10%, said Jeong.

Under the pact, signed in the French capital in 2015, countries have filed pledges for reducing climate-altering greenhouse gas emissions from burning coal, oil and natural gas.

But these goals place the planet on track for warming of more than 3°C, which scientists warn will lead to life- and asset-threatening superstorms, sea-level rise, floods and drought.

"Because present mitigation policies do not appear to be sufficient to achieve the 1.5°C temperature goal, more efforts to mitigate global warming are therefore urgently needed to reduce the spread of aridification," the study authors said.

Source: AFP