Climate change will likely help turn Hurricane Florence into a raging rain machine by dumping 50 percent more water than it would have without global warming, according to a study that for the first time has modeled climate change’s role in a hurricane before landfall.
Human-driven global warming will also make Florence about 50 miles larger in diameter than it would be otherwise, said the analysis from Stony Brook University, the Lawrence Berkeley National Laboratory and the National Center for Atmospheric Research.
The analysis is unusual because it created what the researchers described as a “near real-time experimental forecast” of the size, intensity and rainfall of Florence by taking into account humans’ role in climate change.
Florence, currently a Category 3 hurricane, is set to make landfall along the coast of North Carolina Thursday night or Friday. It’s expected to tear through North and South Carolina over the weekend, dumping huge amounts of rain along its path.
The analysis was based on forecasts the researchers produced Tuesday night that looked at the force of Florence with and without climate change.
Scientists have long worked to establish how global warming impacts hurricanes—explaining how warmer ocean waters are providing more moisture and energy for storms, among other influences—and more recent work, called attribution science, has detailed how much impact climate change has on particular storms.
Until now, however, researchers made those calculations only after the disasters had swept through communities. A few months after Hurricane Harvey wrecked Texas last August, scientists concluded that its record rainfalls were made three times more likely by climate change.
This type of research is crucial for explaining climate change, which can often seem like a broad and vague term. Understanding how it impacts extreme weather involves complex science and social factors that are not easy to convey to the public.
“Event attribution work is important for two reasons,” said Michael Wehner, a Berkeley Lab scientist and co-author of the analysis. “The first is that it raises public awareness of the dangers of climate change. As that danger is very real now, as opposed to some distant threat in the future, being able to make attribution statements in real time captures more attention.”
“The second reason is that the work itself exposes interesting science. In this case of Florence, why is the human-induced increase in precipitation so large? The answer is not straightforward and is stimulating other analyses in the changing hurricane structure due to the warming,” Wehner said.
Attribution science has also become important for holding businesses and governments accountable for climate impacts.
The wave of climate liability suits filed by various communities across the country over the past year have cited studies that have emerged in recent years, showing that 90 companies worldwide have been responsible for the majority of carbon dioxide and methane emissions since the 1850s.
Those companies, dubbed the Carbon Majors, were the focus of a 2017 research paper that tied the amount of carbon emissions and their contributions to rising temperatures over time to specific fossil fuel producers.
“As science evolves, we will be able to narrow and attribute specific climate damages to individual corporations that extract carbon and make carbon fuels available to the global market for decades,” said Richard Heede, co-author of the 2017 paper and co-founder of the Climate Accountability Institute. “It’s important to understand what humanity has caused and will cause so that we can accelerate policies to reduce emissions that are aligned with science.”
Studies by Heede and others have underpinned the growing number of lawsuits seeking compensations from fossil fuel companies for the property and public health damage caused by climate impacts such as intense storms and sea level rise. San Francisco, Oakland, Boulder, Colo., and New York City have filed suits and Rhode Island became the first state to file such a lawsuit in July.
Heede also recently testified before the Human Rights Commission in the Philippines, which is investigating whether fossil fuel companies have committed human rights violations in their conduct surrounding climate change.