AUSTIN (KXAN) — A new University of Hawaii study found that intense category four and five hurricanes are forming earlier each decade as the climate changes.
The research was co-authored by University of Hawaii professor of atmospheric sciences Pao-Shin Chu, who also serves as the Hawaii State Climatologist. Chu and his team found that since the 1980s, hurricanes with wind speeds of 131+ miles per hour are developing three to four days earlier each decade as the climate warms. That means intense hurricanes are now developing two to three weeks earlier than they did 40 years ago.
The authors cite the earlier onset of favorable ocean conditions as the reason.
While changes in the number and intensity of hurricanes in a changing climate are fairly well-studied, little was known about the seasonality of the storms before Chu and his co-authors conducted this study.
By analyzing satellite data, historical tropical cyclone tracks, rainfall records and various statistical methods, the authors of the study found a shift in intense hurricanes from being most frequent in autumn to now being most frequent in the summer — a trend observed since the 1980s in most tropical oceans. The effect was most-pronounced off the west coast of Mexico, the Gulf of Mexico, and the east coast of Florida, among other regions of the globe farther from the U.S. The study cites Hurricane Harvey as an example, a major category four storm that hit Texas in August 2017, killing more than 100 people.
It is important to note that this shift in seasonality is not a projection — it is a trend that is already being observed.
Using computer modeling, Chu and his team were also able to project how the seasonality of intense hurricanes may change in the future. The authors predict that this trend will be amplified, with storms continuing to come earlier each decade — especially if manmade carbon emissions go unchecked.
“Given the seasonal advance of intense tropical cyclones, as shown in this study, the potential for simultaneous occurrence with other high-impact weather events should be a serious concern for the society,” Chu said in a University of Hawaii publication. “Understanding potential changes in hurricane activity in response to global warming is important for disaster prevention, resource management and community preparedness.”