Financial and volunteer support to preserve the unique ecology and cultural heritage of Fakahatchee Strand Preserve State Park and to educate the public about its importance.

Brrrr, is it cold

by Patrick Higgins, President, Friends of Fakahatchee

Wading birds trying to warm up in the day’s first rays of light, in the marsh south of US 41.

It’s certainly been cold lately, but despite the U.S. President’s mistaken conflation of the terms ‘weather’ and ‘climate’ by wishing for a little bit more global warming, our recent cold snaps don’t negate the overwhelming evidence of climate change. While we are shivering here in Florida with iguanas in cold shock dropping out of trees, on the other side of the planet they’re sweltering. Australia’s flying foxes are falling down dead from heatstroke and baby green sea turtles there, whose sex is determined by nest temperature, are hatching out 99% female.

Whilst we can’t positively state any particular individual event is the direct result of climate change, atmospheric concentrations of CO2 and the annual average global temperature are both continuously rising. According to NOAA, global surface temperatures since 1970 have been rising on average twice as fast as for the entire period of recorded observations from 1880-2015. This warming isn’t necessarily uniform around the world, but it’s all about the average. An increase of 0.3° F every decade may not seem much, but when you consider Earth’s 196.9 million square mile surface area, that’s one that one heck of a lot of extra energy going into our climate system. This rapid increase is ten times faster than the average paleoclimate rate of warming during ice-age recoveries.

From the very beginning of the debate on global warming, climate modeling predicted increases in extreme weather. Worldwide record breaking weather events from heat waves, floods, droughts, wildfires and super-storms – both summer and winter – seem to bear this out. Every summer, every winter, every year seems to set a new record. For example, globally 2017 was the second warmest year on record, and the warmest on record without an El Niño’s influence. And weather patterns are changing too; for the first 5 months of 2017 we had 5 inches of rain and for the second 5 months, 5 feet of rain!

As for the 2017 Atlantic hurricane season, there were 17 named storms, ten of which were hurricanes. These hurricanes formed consecutively, without the usual weaker tropical storms in between and six were major category 3 or higher hurricanes. Harvey in August brought the largest amount of rain from any tropical system on record – over 5 feet, causing Houston $200 billion of damages. This was the third ‘once in 500 years’ flood Houston has suffered in the past 3 years! Irma, which devastated the Caribbean (not to mention the damage it caused here), was one of the strongest Atlantic hurricanes ever, with sustained winds of 185 mph that lasted 37 hours – longer for that wind intensity than any tropical system anywhere else in the world. And then there was Hurricane Ophelia, which reached Spain and Portugal – the farthest east any major Atlantic hurricane has ever gone. Get the picture?

So it was with interest and a freeze warning, clad in my Berghaus mountaineering jacket, hat and gloves, that I set out in the dark on the morning of the 18th of January to record what was forecast to be the park’s coldest day yet of the year. I caught a few good photos of shivering wading birds trying to catch the first rays of warming light in a grey landscape en route through the southern reaches of the park.
I only recorded a low of 36°F. For my purposes it was not as cold as I had hoped, although I don’t think Park Manager Steve Houseknetch was as disappointed as I was. I found him in the park office warming his hands in front of an open oven door, wearing what was probably the only Florida Park Service winter parka in all of South Florida. The building’s heater had failed.

During my park visit that day there were no signs of frost along Janes Scenic drive. On the way up I crossed over the sensor hose of the newly installed traffic counter by the water treatment plant. It will give us a much better idea of visitor numbers. I stopped periodically to take some temperature measurements. At 7:25 AM at Six-Pipe Slough, with a nip on the tip of my nose, I recorded an air temperature of 37.6°F. The water temperature at a 1 foot depth, 3 feet into the slough was 54°F, a difference of 16.4°F. A few dead cichlids were caught in eddies; these cold snaps are good at culling some of our exotic fishes.

No doubt had I been more enthusiastic and penetrated a few hundred feet in to the slough, I would have found a higher air temperature. The swamp has a moderating effect. Even in the dry season the humidity radiated from accumulated peat is trapped by the forest canopy so it’s always a little cooler in the summer and a little warmer in the winter. As the sun rose it began to cast long cold shadows, I heard the distant drumming of a woodpecker, punctuated by the languorous argh, argh of a great egret gliding overhead to its morning feeding station. Finally, the sporadic twit-twitting of some small warblers could be heard as the swamp woke up.
Whereas alligators are at the southern limit of their range and have no problems dealing with these, or even freezing temperatures, this is not the case for the American Crocodile found in our brackish waters nearer the Gulf. They are at the very northern limit of their range and are very susceptible to cold. Over 150 dead American crocodiles were identified during aerial and boat surveys immediately after the severe cold snap in 2010. Apparently, rather than taking shelter in what is usually warmer water, they will continue to bask as the temperature drops, sometimes leading to fatal results. But by the time I was driving back home around 10:00 AM our alligators were hauling their black bodies in numbers out of the canal to catch the sun.

Unfortunately, although the cold weather slows the activity of Burmese pythons, the Conservancy of SW Florida reports that our local radio-collared specimens seem to be have weathered this particular cold spell fairly well, as they can seek shelter in deep undergrowth and in armadillo and gopher tortoise burrows. A prolonged deep freeze is needed to hit them hard. The recent cold weather may, however have hindered the expansion of their range northward in the State

The Gulf waters are currently in the low 60s, which is too cold for our manatees. They go into cold stress when the water temperature drops below 68° and need to seek out natural warm water springs in places like the Faka-Union Canal and Henderson Creek. The outlets of power plants or areas of deeper water where a salty bottom layer may trap heat are other refuges from the cold. Our sea turtles have also suffered. Some 900 cold-stunned marine turtles were rescued throughout Florida as a result of this recent cold spell; they have since been released.

Three days after our record low, the afternoon air temperature has risen to the 80’s, long trousers are put away and shorts on again until the next cold wave comes through. Fingers crossed; the days are getting longer and there won’t be too many more. Happy New Year to everyone.