Does Climate Change Cause Extreme Weather Events?
Excerpt:
In 2003, a deadly heat wave struck Europe that would usher in a new era of climate science. In July and August alone, temperatures upward of 115 °F claimed nearly 70,000 lives. However, while average global temperatures have increased at a steady clip since the mid-20th century, strong heat waves had been documented from time to time before then. For climate scientists, that meant that attributing the heat wave to global warming would be next to impossible.
So when a team of British researchers used environmental data and model simulations to establish a statistical link between climate change and the heat wave, they got attention.
Though they couldn’t prove that global warming had “caused” the scorcher, the scientists did assert that warming from human emissions had doubled the risk of extreme weather events. Publishedin Nature, their first-of-its-kind study launched the new field of “attribution science,” which uses observations and models to tease apart the factors that lead to extreme climatic events.
Thanks to advances in supercomputing and pooling hundreds of climate models developed by researchers across the world, they are also more statistically confident than ever in saying that intense storms, droughts and record-breaking heat waves are occurring with increased frequency because of humans. “Ten years ago we wouldn’t have been able to do so,” says Ken Kunkel, a climate scientist at North Carolina State University who also works with the National Oceanic and Atmospheric Administration.
But teasing apart individual weather events is harder. The planet’s history is dotted with unexpected, prolonged heat waves and sudden damaging storms far before humans began pumping out greenhouse gases. “The big challenge is that these kind of extreme events have always happened,” says Kunkel, whose work focuses on heavy storms that cause considerable damage in the U.S. But, he says, “Can you say, ‘This event was caused by global warming? No.‘”