Over a quarter of the planet’s land surface could become arid if global temperatures rise 2ºC above pre-industrial levels, new research suggests. This would lead to droughts and wildfires, with a dramatic impact on agriculture. According to the study published January 1 in the journal “Nature Climate Change”, limiting global warming to under 1.5ºC would avoid extreme changes for most of the threatened areas. The international team of scientists, led by the Southern University of Science and Technology (SUSTech) in Shenzhen China and the University of East Anglia (UEA), studied projections of 27 global climate models. They identified the areas of the world which will become substantially drier when compared to the year-to-year variations they experience now, as global warming reaches 1.5ºC and 2ºC above pre-industrial levels.

The research team found that a global temperature rise to 2ºC would increase the risk of drought and wildfires. “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,” said Dr Chang-Eui Park from SusTech, one of the authors. The study predicts that aridification would emerge over about 20-30 per cent of the world’s land surface by the time the global mean temperature change reaches 2ºC. However, limiting global warming to under 1.5ºC would mean that two thirds of the affected regions could avoid significant aridification. “Early action for accomplishing the 1.5 °C temperature goal can therefore markedly reduce the likelihood that large regions will face substantial aridification and related impacts,” the abstract reads.

According to the authors, 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. “The areas of the world which 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 per cent of the world’s population live today,” said Prof Tim Osborn from UEA. (ab)