Researchers are not sure if climate change caused by humans will lead to longer or more active seasons of hurricanes in the future. However, there is wide agreement that global warming is changing storms.
In less than 24 hours, storms can intensify rapidly, going from weak tropical storms up to hurricanes of Category 3 and higher. This often surprises forecasters, leaving residents with little time to prepare.
Scientists claim that unusually high temperatures on the surface of the Atlantic Ocean have contributed to increased storm activity.
James P. Kossin is a climate scientist at the National Oceanic and Atmospheric Administration. He said that it's likely that climate change caused by humans contributed to this anomalously warm sea. Climate change makes it more likely that hurricanes will behave in certain manners.
Here are a few of them.
Higher winds. Scientists agree that hurricanes have become more powerful.
Hurricanes can be complex. However, one factor that is crucial to determining how powerful a storm will become in the end is the ocean surface temperature. This is because the warmer the water, the more energy it provides for storms. Hurricanes can reach higher maximum sustained winds when the surface temperature is higher.
Kerry Emanuel is a professor of atmosphere science at Massachusetts Institute of Technology. He said, "Potential intensities are increasing." We predicted that it would increase 30 years ago and observations confirm this.
According to the National Hurricane Center, rapid intensification is defined as an increase in maximum sustained winds of at least 35 m.p.h. or 30 knots over a period of 24 hours. Researchers found that since 1980, the probability of a storm experiencing rapid intensification increased from 1 to 5 percent.
Winds stronger than normal can cause power lines to be downed, roofs to be damaged, and coastal flooding will worsen when combined with sea level rise.
More rain. The amount of water that can be held in the atmosphere increases with warming. Every degree Celsius of heating allows the air hold 7 percent more water.
This means that we can expect more rain in the future.
Slower storms. Scientists do not know yet why storms move more slowly. Some believe that a slowdown of global atmospheric circulation or global winds could be partially to blame.
In a paper published in 2018, Dr. Kossin stated that hurricanes have slowed by 17 percent over the United States since 1947. He said that combined with an increase in rainfall rates, storms cause a 25 per cent increase in local rain in the United States.
Flooding is also worsened by slower, more wetter storms. Dr. Kossin compared the problem with walking around the backyard while spraying water on the floor. The water will not have time to pool if you walk quickly. He said that if you walked slowly, you would get a lot more rain.
Climate change increases the area where hurricanes form because warmer water fuels them.
Kossin stated that tropical cyclones are moving away from the tropics to subtropics or middle latitudes. This could lead to more storms hitting higher latitudes like the United States or Japan.
Researchers say that as the climate warms up, storms will intensify faster. Although they are unsure why this is happening, the trend seems to be clear.
Dr. Emanuel, in a paper published in 2017 based on hurricane and climate models, wrote that from 1976 to 2005, storms with rapid intensification -- those whose wind speeds increased by 70 miles an hour or more within 24 hours of landfall -- were uncommon. He estimated that the likelihood of such storms in those years was about one per century.
He found that by the end of 21st Century, these storms could form every five to 10 years.
Forecasters can be hampered by the rapid intensification and intensity of hurricanes, which affects their assessments.
Dr. Emanuel explained that the window of opportunity to make a choice is getting smaller. If officials issue an order to evacuate too soon, they could send hundreds of thousands and even millions into a frenzy, clogging up highways and transit systems. This could in some cases be more costly, dangerous and disruptive than staying put.
Dr. Emanuel stated that it was a forecaster’s nightmare. He said that if a tropical storm, or Category 1 Hurricane, develops overnight into a Cat 4 hurricane, "there is no time to evacuate the people."