An international team of researchers led by the University of East Anglia have determined that many regions of the planet will become substantially drier if global warming reaches 2 degrees Celsius. In fact, the team has determined that over 25 percent of the world will experience less moisture and will be more prone to drought and wildfires.
The experts also found that limiting the increase in global temperatures to under 1.5 degrees Celsius could drastically reduce the amount of the land that will suffer significant changes.
By combining calculations of precipitation and evaporation, scientists can measure the dryness of the land surface, which is also known as aridity. The research team analyzed projections from 27 climate models to identify the regions of the planet which will have the biggest changes in aridity as global warming continues.
“Aridification is a serious threat because it can critically impact areas such as agriculture, water quality, and biodiversity,” said study co-author Dr. Chang-Eui Park. “It can also lead to more droughts and wildfires – similar to those seen raging across California.”
Dr. Park said that as humid regions become increasingly dry, there is “a shift to continuous moderate drought conditions, on top of which future year-to-year variability can cause more severe drought.”
He explained that a rise in temperatures by 2 degrees Celsius would lead to the further aridification of 15 percent of semi-arid climates.
“Our research predicts that aridification would emerge over about 20-30 percent of the world’s land surface by the time the global mean temperature change reaches 2C,” said study co-author Dr. Manoj Joshi. “But two thirds of the affected regions could avoid significant aridification if warming is limited to 1.5C.”
Study author Dr. Su-Jong Jeong pointed out that the world has already warmed by 1 degree Celsius. “But by reducing greenhouse gas emissions into the atmosphere in order to keep global warming under 1.5C or 2C could reduce the likelihood of significant aridification emerging in many parts of the world,” he said.
Over the past couple of decades, drought severity has been increasing across the Mediterranean, southern Africa, and the eastern coast of Australia. Meanwhile semi-arid areas of Mexico, Brazil, southern Africa and Australia have had some fertile land transition to desert.
“The areas of the world which would most benefit from keeping warming below 1.5C are parts of Southeast Asia, Southern Europe, Southern Africa, Central America and Southern Australia – where more than 20 percent of the world’s population live today,” said co-author Professor Tim Osborn.
The findings are published in the journal Nature Climate Change.