Climate Change Makes Fierce Winter Storms Like Éowyn Even Stronger

Winter Storm Éowyn pummeled Ireland and the UK with hurricane-force winds on Friday, creating blackouts for hundreds of thousands and disrupting travel across northwestern Europe.

Éowyn was one of the strongest storms to hit the region and likely set new intensity records after undergoing “explosive cyclogenesis,” according to preliminary estimates from meteorological officials. Meteorologists are still calculating Éowyn’s toll, but the UK Met Office says the storm’s 114 mph (184 kph) gust near Mace Head is likely the strongest ever recorded in Ireland. And Éowyn’s low pressure — a key measure of a storm’s destructive potential — appears to be the lowest recorded in Northern Ireland since 1900.

While there hasn’t been a study attributing the exact influence a warmer atmosphere had on Éowyn’s ferocity, it’s exactly the type of storm expected to become stronger as the climate warms. Research indicates that while climate change could mean fewer winter storms overall in northwestern Europe, it could make strong storms like Éowyn even stronger.

“Storms like this are more likely as the world continues to get warmer,” said Matthew Priestley, a research fellow at the University of Exeter.

Climate change doesn’t necessarily spin up individual storms on its own. Instead, it acts like a volume controller, amplifying what’s naturally there. The added heat in the atmosphere leads to more evaporation from oceans. That releases energy that can power storms while a wetter atmosphere leads to more precipitation falling down. When these juiced-up storms make landfall, they have greater potential to pose a risk to people and infrastructure.

Research shows climate change is making winter and autumn storms in the UK and Ireland wetter — a 20% increase in rainfall that is expected to worsen, fuel more flooding and disruptions to water systems, transportation networks and daily life.

Ireland and the UK, in particular, are in a bullseye, Priestley said. They’re near the Atlantic Ocean, the breeding ground for strong winter storms, and located along a path that can line up low-pressure systems with the jet stream funneling out of the US.

In Europe and elsewhere outside the tropics, there might actually be fewer storms due to a quirk of global heating: The Earth is warming faster at the poles and creating a smaller temperature gradient with lower latitudes. That has the potential to reshape the jet stream, which is affected by that gradient.

That fast-flowing river of air is “basically pushing these storms across the Atlantic very fast towards us,” said Hayley Fowler, professor of climate change impacts at Newcastle University. But if it weakens or shifts in direction, as some climate models predict, that would alter how these storms affect northwestern Europe, she added.

“We see these two opposing factors, of an overall reduction, but the strongest storms to potentially get stronger,” said Priestley. His research shows there will be about 5% fewer storms by the end of the century but a 4% uptick in extreme northern hemisphere winter cyclones.