HurricanesClimate Change Causes Landfalling Hurricanes to Stay Stronger for Longer

Climate change is causing hurricanes that make landfall to take more time to weaken, reports a study just published in  Nature.

The researchers showed that hurricanes that develop over warmer oceans carry more moisture and therefore stay stronger for longer after hitting land. This means that in the future, as the world continues to warm, hurricanes are more likely to reach communities farther inland and be more destructive.

“The implications are very important, especially when considering policies that are put in place to cope with global warming,” said Professor Pinaki Chakraborty, senior author of the study and head of the Fluid Mechanics Unit at the Okinawa Institute of Science and Technology Graduate University (OIST). “We know that coastal areas need to ready themselves for more intense hurricanes, but inland communities, who may not have the know-how or infrastructure to cope with such intense winds or heavy rainfall, also need to be prepared.”

Many studies have shown that climate change can intensify hurricanes – known as cyclones or typhoons in other regions of the world – over the open ocean. But this is the first study to establish a clear link between a warming climate and the smaller subset of hurricanes that have made landfall.

The scientists analyzed North Atlantic hurricanes that made landfall over the past half a century. They found that during the course of the first day after landfall, hurricanes weakened almost twice as slowly now than they did 50 years ago.

“When we plotted the data, we could clearly see that the amount of time it took for a hurricane to weaken was increasing with the years. But it wasn’t a straight line – it was undulating – and we found that these ups and downs matched the same ups and downs seen in sea surface temperature,” said Lin Li, first author and PhD student in the OIST Fluid Mechanics Unit.

The scientists tested the link between warmer sea surface temperature and slower weakening past landfall by creating computer simulations of four different hurricanes and setting different temperatures for the surface of the sea.

Once each virtual hurricane reached category 4 strength, the scientists simulated landfall by cutting off the supply of moisture from beneath.

Li explained: “Hurricanes are heat engines, just like engines in cars. In car engines, fuel is combusted, and that heat energy is converted into mechanical work. For hurricanes, the moisture taken up from the surface of the ocean