CLIMATE CHALLENGESWhat's the Link Between Global Warming and Extreme Weather?

By Jan D. Walter and Beatrice Christofaro

New York authorities have called it the “blizzard of the century.” A ferocious snow storm has gripped parts of the United States from north to south, killing at least 34 people. 

Millions were left without power, trapped in their cars and stranded at airports as the country was plunged into a bone-chilling freeze. A polar vortex had brought cold air from the Arctic down to the US. 

But Americans aren’t the only ones battling extreme weather this holiday season. Torrential rain in the Philippines caused flash floods that killed 13 people and displaced thousands. And the Horn of Africa continues to battle the most severe drought in decades. 

These catastrophes have many pointing their fingers at the climate crisis. 

That heating the planet by burning fossil fuels is broadly making extreme weather more frequent and intense is well-established. Scientists have been sounding the alarm bells on that for years. 

But can we determine how big a factor climate change plays in specific natural disasters? Establishing a direct causal link between rising global average temperature and a single storm, for instance, is difficult and an evolving science.

“Extreme weather has always existed and will always exist,” said Sjoukje Philip, a climate researcher at the Royal Netherlands Meteorological Institute. “But climate change might, however, have an impact on the probability or extremity of the extreme weather events.”

Determining climate change’s contribution is exactly what Philip, who works with an international research team at the World Weather Attribution initiative, is trying to do by conducting real-time attribution analysis of global weather events as they occur. 

Does Global Warming Cause Flooding and Heat Waves?
Weather catastrophes are never down to just one cause. They result from natural factors, as well as human-made ones. For instance, large-scale deforestation and paving over green areas that would usually absorb heavy rainfall with concrete and tarmac can worsen flooding.

Climate change is a human factor too, of course, but is never the sole trigger of a weather catastrophe. Its influence depends on the weather phenomenon in question and is weighted differently for each event, said German climatologist Friederike Otto from Imperial College in London and a founder of the World Weather Attribution research team.

Climate change plays a big role for some events, said Otto, “but for most others like heavy rainfall or droughts, it is quite often a relatively small factor compared to others.”