Floridians to Face More Frequent, Intense Heatwaves
By the late 21st century, if
atmospheric greenhouse gas concentrations reach worst-case projections,
Floridians could experience summer heatwaves three times more frequently, and
each heatwave could last six times longer than at present, according to Meteorology
Professor Shawn M. Milrad of Embry-Riddle Aeronautical University.
“More extreme heatwaves in Florida
would have profound impacts on human health as well as the state’s economy,”
Milrad said. “Heatwaves are a silent killer, claiming hundreds of thousands of
lives each year, yet we tend to focus more on the risks associated with sudden,
dramatic events such as hurricanes.”
In May 2015, for example, temperatures as high as 117 degrees Fahrenheit swept across India, causing widespread power outages and killing at least 2,500 people.
In May 2015, for example, temperatures as high as 117 degrees Fahrenheit swept across India, causing widespread power outages and killing at least 2,500 people.
For the time period 2070 to 2099, if
atmospheric concentrations of carbon dioxide -- a key greenhouse gas -- reach
two to three times the current level of 410 parts per million, heatwaves would
also get hotter, rising roughly 7 to 10 degrees Fahrenheit (4 to 6 degrees
Celsius).
This finding was reported by Milrad
and others in their peer-reviewed article, “Floridian heatwaves and extreme
precipitation: future climate projections,” published in the journal Climate
Dynamics. Greenhouse gases – primarily from fossil fuel burning and
deforestation – trap heat near the Earth’s surface, he noted.
Specifically, researchers used surface observations and high-resolution Weather Research and Forecast model simulations to compare current surface air temperatures and rainfall conditions with what would happen near the end of the century under the) IPCC’s gloomiest climate projection.
The team included Milrad, Embry-Riddle graduate Ajay Raghavendra (now at the University at Albany); undergraduate meteorology major Shealynn R. Cloutier-Bisbee; and Aiguo Dai at the University at Albany and the National Center for Atmospheric Research.
The team assessed heatwave risks for
Florida, including the following six cities: Daytona Beach, Jacksonville,
Miami, Orlando, Tallahassee and Tampa.
“All of the cities we assessed
generally showed the same trends,” Milrad said. “The one city that stood out a
bit was Tampa, which showed a very large increase in daily mean and nighttime
minimum temperatures, in our projections.”
Under a very high-level greenhouse
gas scenario, precipitation would also increase following heatwaves, though
this impact might vary from region to region, researchers found. “Florida’s
precipitation, by its convective nature, is quite scattered,” Milrad said.
“So it’s difficult to pinpoint which regions might get hit the hardest with precipitation in the future, but a much warmer atmosphere would hold more moisture, so any given precipitation event would likely bring heavier amounts of precipitation.”
“So it’s difficult to pinpoint which regions might get hit the hardest with precipitation in the future, but a much warmer atmosphere would hold more moisture, so any given precipitation event would likely bring heavier amounts of precipitation.”
Deadly Nighttime Impacts
Because temperatures are increasing
faster at night, Milrad said, heatwaves are already becoming more frequent and
intense at night, versus during the day.
Soaring nighttime temperatures could be particularly troublesome for Floridians in large cities such as Miami, Tampa and Orlando, where the urban heat island phenomenon could amplify heatwaves, given that paved surfaces and concrete trap heat.
Soaring nighttime temperatures could be particularly troublesome for Floridians in large cities such as Miami, Tampa and Orlando, where the urban heat island phenomenon could amplify heatwaves, given that paved surfaces and concrete trap heat.
“Heatwaves can actually take a
greater toll on human health at night because they affect how we sleep,” Milrad
said.
Raghavendra, lead author of
the Climate Dynamics paper and now a Ph.D. student at the
University at Albany, noted that hotter, more frequent heatwaves could disrupt
Florida’s economy, too. “There would also be tremendous pressure on the energy
sector, in particular, to generate enough power necessary to run
air-conditioners and keep people cool.”
Milrad added: “Heatwaves in Florida
aren’t normally something people think about because it’s always hot in
Florida, yet many people still don’t have access to good air-conditioning, and
that makes them especially vulnerable to increasing temperatures.”
