In the Amazon, around the Mediterranean and in parts of Africa and Australia, droughts are increasing due to a decrease in rainfall. Other regions, such as Central Europe, Canada and Siberia, are experiencing a more erratic climate due to global warming, during which periods of drought will intensify.
This is the conclusion of a new study by Australian climatologists, which is published in the journal Geophysical Research Letters . The researchers have put a new generation of climate models to work to calculate whether their own country will experience the extreme drought and forest fires that Australia has faced in recent years.
Subtropical areas become drier due to a decrease in rain
Because these models have global coverage, the study also provides conclusions for other areas. This shows that large parts of the world are faced with an increase in drought risks, but through different mechanisms.
The strongest increase is for some subtropical areas, which are often already dry or in a transition area between a wet and dry climate. Not only do these areas heat up above average, increasing evaporation, but they can also experience decreasing rainfall on an annual basis.
Examples include the Mediterranean, the Amazon in South America and southwestern Africa and southwestern Australia, according to the new research.
Elsewhere an increase in drought risk due to more irregular precipitation and an increase in evaporation
In other parts of these continents, annual rainfall may increase due to climate change, but that does not automatically mean that the drought risk is reduced. For example, according to the study, most areas on Earth will have an increase in drought intensity because precipitation is expected to become more erratic: lots of rain in a short time, followed by periods of no rainfall. This applies, for example, to East Africa, but also to many areas of the moderate latitude of North America, Europe and Asia.
In addition, evaporation increases everywhere due to a rise in temperature, so that a period of dry weather leads to dehydration of the vegetation and the soil. The researchers cited Central Europe as an example of a region with an annual increase in rainfall and an increasing risk of drought.
"We found the most robust results yet for future droughts with the new climate models," said lead author Anna Ukkola of the Australian Climate Research Center CCRC. "The increase in the duration and intensity of droughts was directly linked to the increase in greenhouse gases in the atmosphere."
According to Ukkola, the extent to which droughts increase depends on the level of future greenhouse gas emissions - the higher the emission scenario, the stronger the effect.
See also: Climate change does increase the risk of forest fires in Australia
See also: Drought in Achterhoek can already be attributed to climate change