Authors of a new report say they have "high confidence" that some extreme weather events such as droughts, heat waves and heavy precipitation are being influenced by human-caused climate change.
A committee of climate researchers from British and American universities, working under the auspices of Washington's National Academies of Sciences, Engineering and Medicine, laid out its findings Friday at a news conference.
In the past, scientists generally said the coincidence of specific episodes of extreme weather and climate change had no definitive link.
But the committee collected long-term statistics on extreme events and were able to map out how they were becoming more severe as the effects of climate change piled up over time.
For example, in "Attribution of Extreme Weather Events in the Context of Climate Change," the committee pointed to the 2010 heat wave in Russia that led to the nation's worst drought in nearly 40 years, and the loss of at least 9 million hectares of crops.
The members also noted the extreme rain in the United Kingdom in 2000 that caused the worst widespread flooding since the 1940s.
The researchers said they didn't yet have enough information to blame every specific event on climate change. But they said that as more research is done, scientists' understanding might expand to the point at which they will be able to link climate change to cyclones, wildfires, and severe convective storms that can lead to tornadoes.
The information is important because as these extreme events become worse and more common, the effects can be quantified in dollars and lives. In 2014, for instance, the World Meteorological Organization estimated that extreme weather events cost humanity over $2 trillion and killed more than 2 million people.
"Understanding that risk is crucial for governments and businesses," said David Titley of Pennsylvania State University, the committee's chairman. "For example, if you're managing a business, you may need to know whether there may be more droughts in the future, because they may impact supply chain logistics and, ultimately, your bottom dollar."
The report called for building upon its findings with additional research in the hope that forecasters and researchers can eventually develop better predictive models based not just on our understanding of climate, but on the knowledge of the impact that climate change is having on individual weather systems.
