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It's Hot But Don't Blame Global Warming


Geographer Morton Winsberg’s research suggests that local land-use changes — urban development and draining wetlands — may be contributing more to local climate change than global warming. [Photo: Jeffrey Camp]
Morton D. Winsberg fell in love with Florida more than 50 years ago, but the Illinois-born geographer never quite got used to the dog days of summer.

In recent years, the Florida State University professor emeritus and author of a book called “Florida Weather” began wondering: Is global climate change making Florida’s hot season longer and hotter? With help from geography students and researchers at FSU’s Population Center and Florida Climate Center, Winsberg and co-author Melanie Simmons gathered and analyzed temperature data from 57 Florida weather stations going back six decades.

Their research showed that the hot season in Florida has gotten a lot hotter — and longer — in some places, but not at all in others. The change, however, is unrelated to global warming, the increase in the average temperature of the earth’s atmosphere. Rather, they found, it’s a function of the lesser-known phenomenon of local warming. The analysis “shows that weather can be very local,” says Winsberg, “and also that weather can be a function of population growth.”

Winsberg found the most notable climate changes along the state’s southeastern coast, where development and wetlands drainage have been heaviest. In most areas he analyzed, the heat is getting more intense. Of the 57 weather stations, 49 saw an increase in the number of days with an average temperature of 80 degrees. When it came to the length of the hot season, the biggest increase was in Hialeah, with a 72-day increase, followed by Miami, with a 45-day increase.

Neither the intensity of the heat nor the increasing number of hotter days was related to water temperatures in the Atlantic and Gulf, a fact that surprised Winsberg. The heat trends also weren’t consistent across the state. In fact, some areas, notably in the northeast part of the state, saw a shorter hot season and a decrease in the number of dog days.

That evidence leads Winsberg and FSU meteorologists to blame the hot spots on local land-use changes that accentuate the urban “heat-island” effect — the pools of heat that large, dense concentrations of people produce in their local climates. Cutting down trees, draining wetlands and pouring concrete all make a place hotter, as anyone who’s walked across an asphalt parking lot on a summer day knows, Winsberg says.

Contagious Energy

Geographer Morton Winsberg retired a decade ago, but you wouldn’t know if from his teaching load, his research output and the hours he spends on the Florida State University campus.

At 78, Winsberg no longer worries about getting his work published or being recognized by fellow academics. He had even been teaching Latin American and Florida geography at FSU for free until last year, when FSU put him back on the payroll. Winsberg is happy taking advantage of office space, grad students and GIS equipment so he can keep digging into weather and other interests.

“I don’t play golf,” he explains. “I prefer to play with aggregate data.”

Winsberg spent his career traveling the globe and writing about 100 research papers on topics as diverse as Jewish agricultural colonization in Argentina and Irish suburbanization in Boston, Chicago and New York. His favorite trip: Backpacking across northern Spain, following a medieval pilgrimage route to Santiago de Compostela, reputed to be the burial site of St. James.

Winsberg says he dreaded becoming the sort of retiree “who kept up with the world via nytimes.com.”

“I wanted to keep feeling useful and to be useful,” Winsberg says. He passed up royalties from his “Florida Weather” book so it would be more affordable ($16.95 at upf.com). In addition to his work on weather, his post-retirement writings include the book “Atlas of Race, Ancestry, and Religion in 21st-Century Florida.” He is currently researching the locations of megachurches, particularly those within metropolitan areas.

Colleagues say he’s the only “emeritus” professor they know who spends as much time on campus as he did before retiring. “I’ve never talked to Mort about weather when he was not extremely excited about it,” says Melissa Griffin, Florida’s assistant climatologist. “He has this energy that flows out of him, seeps out of him, and other people catch it.”


State climatologist David Zierden says Winsberg’s data bolsters his belief, backed up by other Florida studies, that climate changes driven by land use ‘are as important or more important in Florida than what has happened here to date due to greenhouse gases.’ [Photo: Ray Stanyard]

On a regional level, state climatologist David Zierden says, historical records show that southeastern Alabama, Georgia and north and central Florida have not experienced steady warming, but rather relatively warm periods, such as the 1930s through the 1950s, followed by relatively cool periods, such as the 1960s through the 1980s.

Heavily drained or developed areas bucked those trends, however. The most dramatic example in Winsberg’s study is the difference between Belle Glade, in a part of the Everglades drained for sugar production, and undeveloped Everglades City. Since 1950, Belle Glade has seen a 32% increase in its number of dog days, while Everglades City has seen a 3% decrease. The transformation of swampland around Belle Glade to farmland appears to have caused a significant rise in temperatures. “The draining of the Everglades and the upturning of all that black soil has really changed the local climate in that area,” says Zierden.

The idea of local climate change may seem contrarian at a time when scientists and policy-makers focus on global warming and its causes, primarily the release of carbon dioxide and other greenhouse gases into the atmosphere. But Florida’s top global warming scientists, including Harold Wanless, chairman of geological sciences at the University of Miami, agree that greenhouse gases don’t seem to be impacting Florida’s temperatures. When it comes to global warming, Wanless says, sea-level rise — caused by warming elsewhere, particularly the Arctic — is the chief threat to Florida. Wanless predicts Florida’s seas will rise three to five feet by century’s end.

As state and national policy-makers work to mitigate damages from the rising seas, Winsberg says he hopes local officials and Floridians will use his data to think more wisely about land-use changes and wetlands drainage.

“People just dread when the hot season begins, and they are so relieved when it’s over,” says Winsberg. “We don’t want to extend the suffering.”


Map: Morton Winsberg

Go to Links Links: Read Mort Winsberg’s study on Florida’s dog days.
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