Research suggests extreme rain events more likely in dry regions
Extreme rainfall events in desert areas — like recent storms in Death Valley and Chile’s Atacama Desert — may be partly driven by cyclical climate phenomena like El Niño, but such storms could also become more common in coming decades as the global climate warms.
A new study published in the journal Nature Climate Change suggests global warming will boost rainfall in some of the world’s driest regions. Flash flooding in deserts could become commonplace, according to the researchers with the ARC Centre of Excellence for Climate System Science.
“We found a strong relationship between global warming and an increase in rainfall, particularly in areas outside of the tropics,” said lead author Dr Markus Donat. “Within the tropics we saw an increase in rainfall responding to global warming but the actual rate of this increase was less clear.”
Even with increased rain, there probably won’t be new sources of water available for people in arid regions. Warmer temperatures will also lead to increased evaporation, which means that, while there may be more extreme flooding events it may have little impact on overall water storage rates.
“The concern with an increased frequency and in particular intensity of extreme precipitation events in areas that are normally dry is that there may not be infrastructure in place to cope with extreme flooding events,” said Donat. “Importantly, this research suggests we will see these extreme rainfall events increase at regional levels in dry areas, not just as an average across the globe.”
The researchers reached their conclusions after comparing rainfall patterns in dry parts of Australia with dry regions in Asia. At the same time, wetter regions across different countries were also compared. This enabled the scientists to make apples-to-apples comparisons.
Importantly, the findings remained consistent across observations and models.
“With precipitation climate models and observations don’t always tell the same story regarding regional changes, but we were very surprised to find that our results turned out to be highly robust across both,”Donat said.
“It appears the uncertainties in climate models were greatest where the observational uncertainties were greatest. This suggests that improved observations will be vital for those planning for climate change if they are to reasonably determine how future precipitation will change in every corner of the world with global warming,” he concluded.