Global warming turns Florida’s humidity into existential crisis

No need to consult last month’s direst-yet warning (“code red for humanity”) from the United Nations’ Intergovernmental Panel on Climate Change to know that South Florida is cooked. Not on a king tide weekend when storm sewers regurgitate brackish water, inland waterways crest sea walls and low-lying streets become elongated lagoons.

Glaciers are melting, polar ice is disappearing, sea level is rising and the evidence of global warming is washing over some of the state’s most expensive waterfront real estate. With 165 miles of navigable waterways, Fort Lauderdale, the ersatz Venice of America, has something else in common with the great Italian city, where knee-deep canal water covers St. Mark’s Square about 60 times a year.

In either Venice, coastal flooding is regarded as the great existential threat — the awful consequence of climate change that could ruin both communities.

But wait. Let Italy worry about flooded piazzas while South Florida contemplates another simmering disaster. In one of the muggiest regions in America, where the seven warmest years on record were all recorded in the last seven years, we’re nearing a dangerous, possibly lethal combination of heat and high humidity.

Stop sweating rising sea levels. South Florida has another urgent climate catastrophe looming.

Down here in the subtropics, our killer predicament occurs at the intersecting point of heat and humidity, when warm air becomes so laden with moisture that sweat no longer evaporates and cools the body. Scientists can gauge such life-threatening conditions by covering a thermometer bulb with a damp cloth. The heat-humidity combination becomes lethal when moisture stops evaporating and the wet bulb temperature is no different than a dry bulb reading. After a few hours coping with a “wet bulb” temperature of 35 degrees Celsius (95 degrees Fahrenheit), humans suffer organ failure.

Scientists worry that unless humanity can be convinced to keep average global temperatures from rising more than 2.7 degrees — an unlikely prospect — certain communities will become unlivable. Certain communities like ours. And they’ve given us a scary new shorthand term for our coming demise: “web bulb 35.”

Aside from a few nine-eleven-was-a-CIAconspiracy climate deniers who think global warming, like COVID-19, is just another Bill Gates invention, most of us have already accepted that Florida, protruding 500 miles into soupy southern waters, is particularly vulnerable to the calamitous effects of global warming. We know that steamy Florida is America’s canary in the coal mine, with huge population centers clustered along the shoreline, threatened by both coastal flooding and ever-more-powerful hurricanes. Now we can add wet bulb 35 to our apocalypse check-list

“Humid heat is the most underestimated direct, local risk of climate change,” warned Radley Horton of Columbia University’s Lamont Doherty Earth Observatory. Horton is a lead author of a NOAA-sponsored study, published in the journal Science Advances, with the cheery title, “The Emergence of Heat and Humidity Too Severe for Human Tolerance. “As with sea-level rise and coastal flooding, we are already locked into large increases in the frequency and intensity of

extreme humid heat events, and the risk is much larger than most people appreciate.”

The Science Advance study concluded that we’re only a few degrees from the point when prolonged daytime, outdoor activities in places like Florida become unthinkable. “The deadly trends in recent decades toward increasingly extreme humid heat underscore a major societal challenge for the coming decades,” Horton wrote.

The effect on the economy would be devastating. Last month, the Union of Concerned Scientists released a study called “Too Hot To Work,” warning that the outdoor workers in Florida (among other places) were facing an escalating hazard. The UCS reported that Florida’s outdoor workers have historically suffered through an average of 25 days per year with a heat index above 100 degrees. Unless the present global temperature trajectory is dramatically altered, by mid-century, Floridians will experience 105 extremely hazardous work days per year.

“Florida is in the bullseye on all of this,” climate scientist Kristina Dahl, lead author of the UCS study, told the Florida Phoenix. Workers in Florida, unless they abscond to cooler environs, could lose $8 billion in lost earnings a year.

Meanwhile, about three billion other people living in already sweltering environments in Central America, the Mideast, central Africa and southern Asia — most of them without the luxury of air conditioning — face a not-so-distant prospect of unlivable conditions.

They won’t stay put. Along with drought, super storms, floods, wildfires, mosquito-borne diseases and a killer combination of heat and humidity, add a mass migration to the coming disasters from global warming.

But I doubt many international heat refugees will head to Florida. That would be out of the frying pan and into wet bulb 35.