Study predicts a significantly drier world at 2ºC, with aridification of up to 30% of the world’s land surface

Over a quarter of the world’s land could become significantly drier – increasing the threat of drought and wildfires – if global warming reaches 2ºC.

However, limiting global warming to under 1.5ºC would dramatically reduce the fraction of the Earth’s surface that undergoes these changes.

These are the main findings of new research from an international team, including the University of East Anglia, published yesterday (01 January) in Nature Climate Change.

The study is the result of an international collaboration led by the Southern University of Science and Technology (SUSTech) in Shenzhen China and UEA.

Droughts and wildfires

The research team used 27 climate models to locate areas where aridity will substantially change when compared with the year-to-year variations experienced now, as global warming reaches 1.5ºC and 2ºC above pre-industrial levels.

‘Aridification is a serious threat because it can critically impact areas such as agriculture, water quality, and biodiversity. It can also lead to more droughts and wildfires – similar to those seen raging across California.

‘Another way of thinking of the emergence of aridification is a shift to continuous moderate drought conditions, on top of which future year-to-year variability can cause more severe drought. For instance, in such a scenario 15% of semi-arid regions would actually experience conditions similar to ‘arid’ climates today.’

SusTech, one of the authors of the study

Up to 30% of land at risk

Dr Manoj Joshi from UEA’s School of Environmental Sciences said the research predicts aridification would emerge over about 20-30% of the world’s land surface by the time the global mean temperature change reaches 2ºC.

He added that two-thirds of the affected regions could avoid significant aridification if warming is limited to 1.5ºC.

‘The world has already warmed by 1ºC. But by reducing greenhouse gas emissions into the atmosphere in order to keep global warming under 1.5ºC or 2ºC could reduce the likelihood of significant aridification emerging in many parts of the world.’


Drought risk around the world

Drought severity has been increasing across the Mediterranean, southern Africa and the eastern coast of Australia over the course of the 20th century, while semi-arid areas of Mexico, Brazil, southern Africa and Australia have encountered desertification for some time as the world has warmed.

According to Professor Tim Osborn from UEA, the areas of the world that would most benefit from keeping warming below 1.5ºC are parts of South East Asia, Southern Europe, Southern Africa, Central America and Southern Australia – where more than 20% of the world’s population live today.

This work forms part of a partnership between between the University of East Anglia (UEA) and The Southern University of Science and Technology (SUSTech).