Climate models may be underestimating global warming in North America, Europe and other places influenced by extratropical winds, according to a new study published Monday in the journal Communications Earth & Environment.
Extratropical winds shape climate patterns in North America, Europe and other temperate regions, but few climate models account for their variability. Now, scientists suspect a lack of extratropical wind data has undermined long-term temperature and precipitation forecasts.
Extratropical winds drive decadal climate patterns, bringing hot, cold, wet or dry weather to continents for roughly 10 years.
“Variations between decades in the strength of winds in the more temperate regions of the world are a crucial missing ingredient in projections of the future climate of those regions,” lead study author Christopher O’Reilly, research fellow in the meteorology department at Reading’s Royal Society University, said in a press release.
For the study, scientists collected global data on extratropical winds, revealing their variation and influence on climate patterns in North America and Europe.
When scientists incorporated the new data into climate models, they found extratropical forecasts were even more uncertain.
“By adding this extra variability into climate models, we showed that these winds may be an additional source of uncertainty on top of climate change,” O’Reilly said.
“This could mean that within these regions, temperatures are pushed to relatively extreme highs or lows more often. While in some decades they could counteract increases to temperatures and heavy rainfall caused by climate change, in other periods they could make these extremes even more extreme,” O’Reilly said.
Such increases in variability could yield prolonged periods of extreme weather. A particularly warm and wet decade, for example, could increase the risk of damaging hurricanes.
Models showed the range of possible precipitation totals across Northern Europe, Northern America and the Mediterranean could increase by as much as 50 percent, with uncertainty doubling in some regions.
The forecasts also showed that especially dry winters are likely to become increasingly common across the Mediterranean. Europe tends to host more frequent and extreme heatwaves during the summers following dry winters.
“This is yet another reminder that preparation will be crucial as we face up to more variable regional climates as an impact of climate change in the future,” O’Reilly said.