BY OLIVIA MURRELL – STAFF WRITER
The record number of recent hurricanes has many people questioning whether this is a direct result of climate change. Since August, we have seen Harvey decimate the gulf coast of Texas and Louisiana, Irma barreling through Florida, Jose destroy the Bahamas, and Maria wreak havoc on Puerto Rico. Does climate change have an effect on severe weather? Climate science suggests that there is an expected correlation between warmer atmospheric temperature and more severe weather.
According to a Washington Post-ABC News poll, the majority of Americans now say that climate change makes hurricanes more intense. This marks a significant shift in public opinion. About 12 years ago, the majority of the public dismissed climate change as a significant factor in severe weather. On Centre’s campus, Environmental Studies professor Dr. Brett Werner spoke to the Centre Environmental Association (CEA) at the club’s most recent meeting.
CEA President Beka Bruner emphasizes the importance of talking about climate change in our daily lives. She says, “Personal decisions matter and talking about it now is important.” Scientific evidence suggests that climate change plays a role in severe weather. For example, in a hurricane, climate change increases the level of rainfall, the intensity of the storm, and the severity of the storm surge. Warmer air leads to more evaporation, and more evaporation leads to more precipitation.
For every 1°F temperature increase, the atmosphere can hold approximately 4% more water vapor. This leads to increased rainfall and higher chances for flooding. We saw record rainfall dump on Texas from Harvey. Four times as much water fell from Harvey than fell from Katrina. The flood from Harvey is a once-in-a-1,000-years flood. According to Dr. Werner, part of the problem, coupled with warmer air, was a pressure system that situated itself right in Harvey’s path called a blocking pattern. The pressure system acted as a wall that kept Harvey stalled above Texas on August 26, causing a continuous dumping of enormous amounts of water for an extended period of time. He continued to say, “[We] can’t say that it’s climate change, but it was definitely an unexpected and abnormal event.”
Warmer ocean water also provides more fuel for hurricanes and allows them to grow stronger as they form over the oceans. There has been an ocean temperature increase by 1-3°F over the past 100 years, and there is evidence that hurricanes are intensifying at a higher rate than they were 30 years ago. Warmer oceans coupled with land ice melting has caused approximately 7 inches of sea level rise over the past century. This sea level rise dramatically increases the storm surge, or the coastal flooding that occurs before the hurricane makes landfall. These storm surges are pushing farther inland than they used to. In response, Dr. Werner explained, “It could have been much worse with Irma – the storm surge was 3,4, or 5 feet and it could have been 9 [feet].”
As time goes on and the climate continues to change, hurricanes are expected to produce more rainfall, be more intense, and produce more severe storm surges. Scientists usually need about 30 years of information for the kind of data that would be climatologically statistically significant. Right now, that kind of data is still being acquired. Climate scientists can predict, however, that as the global climate changes, so will severe storms. The overall number of hurricanes may not significantly increase, but the storms that do occur will be worse.