New research from ARC Centre of Excellence for Climate Extremes, Australia, says we’ll see longer and more frequent droughts due to climate change.
Image credits Anna M. Ukkola et al., (2020), AGU.
Southwestern Australia, parts of southern Australia, as well as regions in the Amazon, Mediterranean and southern Africa can expect to see more frequent and intense droughts in the future as climate patterns shift across the globe.
At the same time, central Europe and the boreal forest zone are projected to get wetter and experience fewer droughts — but the ones they do get are likely to be much more intense than today.
Rainless
“We found that the increase in drought duration and intensity was directly linked to the amount of greenhouse gases emitted into the atmosphere,” said lead author Dr. Anna Ukkola.”There were only slight changes to the areas of drought under a mid-range emissions scenario versus a high-emissions pathway.”
“However, the change in the magnitude of drought with a higher emissions scenario was more marked, telling us that early mitigation of greenhouse gases matters.”
The team worked with the latest generation of climate models (CMIP6), the same ones being used as a starting point for the next IPCC assessment report on climate change, to examine rainfall-based drought throughout the world in the future.
They explain that most of the previous research into droughts only looked at changes in average rainfall as a metric, giving them a degree of uncertainty.
Image credits Anna M. Ukkola et al., (2020), AGU.
To get a better picture, the team factored in metrics on rainfall variability and mean precipitation levels estimated for the future, and then worked out how that will affect drought patterns in regions across the world.
Drought duration was very closely tied to changes in average rainfall levels, they found, but drought intensity was more closely tied to the interplay between average rainfall and its variability. In other words, the regions that will fare the worse are those which will see less precipitation and shifts in the timing of precipitation throughout the year.
Regions such as the Mediterranean, Central America, and the Amazon, which are estimated to see declines in average rainfall levels, will probably see more frequent and longer droughts. Boreal forests will likely see shorter droughts caused by increased average rainfall, the team explains. The team didn’t find any region that shows an expected reduction in the intensity of future droughts, not even in areas that are likely to see increases in rainfall such as central Europe.
“Predicting future changes in drought is one of the greatest challenges in climate science but with this latest generation of models and the opportunity to combine different drought metrics in a more meaningful way we can gain a clearer insight into the future impacts of climate change,” said Dr Ukkola.
“However, while these insights grow clearer with each advance, the message they deliver remains the same — the earlier we act on reducing our emissions, the less economic and social pain we will face in the future.”
The paper “Robust future changes in meteorological drought in CMIP6 projections despite uncertainty in precipitation” has been published in the journal Geophysical Research Letters.