Are tornadoes linked to climate change? The science isn’t yet definite

Washington, Dec 14 (AFP/APP):Was climate change behind the recent tornadoes that killed dozens of people and wrought a trail of destruction through five American states?

Higher temperatures might create more favorable conditions for these violent storms, but for now, scientists remain cautious about drawing a direct connection.

While research has firmly linked recent extreme weather events to global warming — from this summer’s heatwaves in North America to flooding in western Europe — there remain important gaps in the scientific understanding of twisters and how they relate to climate.

“At least in the past few decades, we have seen a trend towards more favorable conditions,” especially in winter in the country’s midwest and southeast, John Allen, a climatologist at Central Michigan University, told AFP.

But “it is misleading to attribute this event to climate change,” he added.
James Elsner, professor of climatology at Florida State University, draws a comparison with what we know about the connection between fog and car crashes: foggy conditions on the road are associated with a higher number of accidents, but individual crashes in heavy fog aren’t always due to poor visibility.

In the same vein, knowing what the link is between climate change and tornadoes with more certainty requires further investigation.
This is where the field of “attribution science,” which has made enormous strides in recent years, comes in.

The idea is to feed climate data into computer models to analyze the probability specific extreme weather events would have occurred in a world without human-driven climate change, versus the world we live in today.

But such studies take time to carry out and are particularly tricky for tornadoes, which are more difficult to model than other extreme weather phenomena because of a relative lack of data.
It’s even too early to say for sure that climate change will increase the frequency of winter twisters.
“I think you could probably argue that seems to be the way the evidence is pointing. But I don’t think we’re at the point now where we can definitively say ‘yes, this is climate change,'” said Allen.

The latest United Nations Intergovernmental Panel for Climate Change (IPCC) report underlined there was “low confidence” on a link between global warming and small-scale phenomena such as tornadoes, both in observed trends and in projections.