Climate models

Latest climate models show more intense droughts to come •

The latest climate models show more intense droughts to come. Experts at University of New South Wales found that droughts are expected to further intensify as climate change alters precipitation patterns.

Based on new climate models from the ARC Center of Excellence for Climate Extremes, the researchers found that droughts will become longer and more frequent in some regions, and more intense in all regions.

Even in regions like central Europe where more precipitation will lead to fewer dry spells, droughts will be stronger when they occur, according to the study authors.

The researchers used the latest generation of climate models (CMIP6) to estimate the extent of fluctuating rainfall and subsequent drought.

“We found that the new models produced the most robust results for future droughts to date and that the degree of increase in drought duration and intensity was directly related to the amount of greenhouse gases. greenhouse emitted into the atmosphere,” said lead author Dr Anna Ukkola.

“There were only slight changes in drought areas under a medium emissions scenario compared to a high emissions trajectory. However, the change in drought magnitude with a scenario higher emissions has been more pronounced, which tells us that early mitigation of greenhouse gases is important.

In many previous studies, projections of future droughts were based only on average rainfall. This type of research is limited because it does not take into account the variability of precipitation, which increases in parallel with global warming.

By combining measurements of average precipitation and precipitation variability, the current study provides new clarity on upcoming climate-related changes in the intensity and duration of droughts.

The researchers found that the duration of a drought is strongly related to changes in the average amount of precipitation, while the intensity of a drought is more closely related to the variability of precipitation.

Experts have determined that regions with declining average rainfall such as the Mediterranean, Central America and the Amazon will experience longer and more frequent droughts. Meanwhile, regions such as the boreal forests are expected to experience higher average precipitation and shorter droughts.

In terms of drought intensity, however, increased rainfall variability will lead to more severe droughts, regardless of average rainfall. Alarmingly, the researchers could not locate any regions showing a reduction in future drought intensity.

“Predicting future changes in drought is one of the greatest challenges in climate science, but with this latest generation of models and the ability to combine different measures of drought in more meaningful ways, we can gain insight clearer of the future impacts of climate change,” says Dr Ukkola.

“However, while this information becomes clearer with each advance, the message it delivers remains the same: the sooner we act to reduce our emissions, the less economic and social hardship we will face in the future.”

The study is published in the journal Geophysical Research Letters.

By Chrissy Sexon, Personal editor