Hurricane Florence produced more extreme rainfall and was spatially larger due to human-induced climate change, a new study shows.
Previous research has suggested that human influences such as emission of greenhouse gasses that alter climate affects precipitation in extreme storms. The new research, however, is a first to use a “forecast attribution” framework that allows scientists to investigate the effect of climate change on individual storm events days in advance.
Changes in extreme weather are one of the most serious ways society experiences the effects of climate change, researchers say. Severe weather and natural disasters account for a lot of damage and have a major economic impact on areas where they happen.
In 2018, prior to the landfall of Hurricane Florence, researchers used simulations of the storm given climate change models to predict that it would be slightly more intense for a longer portion of the forecast period, rainfall amounts over the Carolinas would see a 50% increase due to climate change and warmer water temperatures, and the hurricane would be approximately 80 kilometers (50 miles) larger due to the effect of climate change on the large-scale environment around the storm.
“With our ability for additional ‘hindsight’ numerical modeling of the storm around climate change factors, we found predictions about increases in storm size and increased storm rainfall in certain areas to be accurate, even if the numbers and proportions are not exact,” says Kevin Reed, assistant professor in the School of Marine and Atmospheric Sciences at Stony Brook University.
“More importantly, this post-storm modeling around climate change illustrates that the impact of climate change on storms is here now and is not something only projected for our future.”
While the post-storm analysis did show that the storm was slightly more intense during the forecast period due to climate change—as they predicted—as measured by minimum surface pressure and near-surface winds, the finding remains the most uncertain from the hindsight model.
One key finding of the post-storm model showed that Hurricane Florence was about nine kilometers larger in mean maximum diameter due to climate change. Additionally, rainfall amounts over large ranges increased significantly.
Mean total overland rainfall amounts associated with the forecasted storm’s core increased 4.9 ± 4.6% with local maximum amounts experiencing increases of 3.8 ± 5.7% due to climate change.
Attributing climate change effects to individual storms, as researchers did with Hurricane Florence, will allow scientists to better communicate the direct impacts of climate change on extreme weather to the public, Reed says.
The research appears in Science Advances. The Stony Brook Foundation, National Science Foundation through the National Center for Atmospheric Research, and the Department of Energy’s Office of Science supported the work.
Source: Stony Brook University