Forecasts could be underestimating extreme weather events

Climate change is driving unprecedented hot spells and downpours faster than forecasted by historical trends, a new scientific study has suggested.

Published yesterday in the journal Science Advances, the study found that predictions relying only on historical observations have underestimated the number of extremely hot days in Europe and East Asia, and extremely wet days in the US, Europe and East Asia, by around half.

Research author and climate scientist at Stanford university, Noah Diffenbaugh, said that even small increases in global warming can cause large upticks in the probability of extreme weather events, particularly heat waves and heavy rainfall.

“We are seeing year after year how the rising incidence of extreme events is causing significant impacts on people and ecosystems,“ he continued.

“One of the main challenges in becoming more resilient to these extremes is accurately predicting how the global warming that's already happened has changed the odds of events that fall outside of our historical experience.“

Engineers, land-use planners and risk managers have used historical weather observations from thermometers, rain gauges and satellites to calculate the probability of extreme events for decades.

Scientists trying to isolate the influence of human-caused climate change have struggled as there are relatively few such events in the historical record, and global warming is changing the atmosphere and ocean in ways that may have already affected the odds of extreme weather conditions.

In the new study, Diffenbaugh used the frequency of weather events from 2006 to 2017 to evaluate the predictions his group had made using data from 1961 to 2005. He found that, in some cases, the actual increase in extreme events was much larger than what had been predicted.

“The method actually worked very well for the period that we had originally analysed – it's just that global warming has had a really strong effect over the last decade,“ he continued.

“The good news is that these new results identify some real potential to help policymakers, engineers and others who manage risk to integrate the effects of global warming into their decisions.“

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