Photo by NASA, Public Domain
(Click on the following link to listen to an audio version of this blog … Climate Change and the Florida Keys
On the NASA sponsored website, “Global Climate Change: Vital Signs of the Planet,” the current state of our warming planet is very clearly described. The past nine years have been the warmest on record since record keeping began back in 1880. Earth in 2022 is about 2 degrees F warmer than the late 19th Century average. Over the next few decades global temperatures are expected to rise another 3 degrees F.
The impacts of these rising temperatures will be widespread: polar ice caps and mountain glaciers will melt, weather patterns will be altered and tropical storms and hurricanes will become more severe. Climate change will cause drought in some parts of the world which will, in turn, lead to expanded wildfires, and it will also cause more rain to fall in other parts of the world leading to increased flooding. Everything, though, everywhere, will change.
Climate change is occurring because of rising levels of carbon dioxide in the atmosphere. Atmospheric carbon dioxide had been for the past 10,000 years, 280 ppm (parts per million). This changed, though, in the mid-Seventeenth Century. Then, the accelerated burning of fossil fuels associated with the Industrial Revolution began to add gigatons upon gigatons of carbon dioxide to the atmosphere. As of May 2022 the atmosphere contained 421 ppm carbon dioxide.
Photo by D. Sillman
In the American West, recent decades of prolonged drought and the massive, unrelenting wildfires may be early indications of climate change’s impact. The loss of the glaciers in Glacier National Park is another very graphic indication of change. Many authorities, though, feel that the “ground zero” for the effects of climate change in the United States will be the Florida Keys.
The Keys, as I wrote back in my first Florida blog (Signs of Winter 5, January 5, 2023), are, on average, only six feet above sea level. These, low, limestone and coral islets stretch out over 180 miles and are exposed to the currents, the waves and the storms of the Atlantic Ocean to their east and the Gulf of Mexico to their west. Driving along the highway that connects Key Largo with Key West you realize that the Keys are just barely land at all.
Sea level rise is a major feature of all climate change models. Just how much the oceans will rise varies from model to model, but a range of 1 to 8 feet has been projected for the Keys.
Mapby NOAA. Public Domain
The Nature Conservancy at their sea level monitoring site on Big Pine Key estimate that 96% of the island would be inundated if sea levels rise “just” 4.6 feet. They also estimate that the property damage throughout the Keys from a sea level rise of this magnitude would be $43 billion dollars. They also project that the protective mangrove forests on the coasts will be inundated with sea water, and the beaches needed for sea turtle nesting will be lost. The interconnected ecosystems of the Keys (the mangroves, the seagrasses and the coral reefs) will all be severely damaged.
A report by the National Marine Sanctuary (NOAA) entitled “Climate Change Impacts: Florida keys” outlines the specifics of the impacts of the changing climate on the Keys.
Temperatures of the ocean waters surrounding the Keys have increased 1.4 degrees F since 1970. This temperature rise has caused many marine species to move north into cooler waters or into cooler, deeper, ocean habitats. These higher temperatures have negatively affected the larvae of the Florida stone crab and threaten the $30 million a year stone crab industry. Yearly stone crab catches (measured by harvested claws) have declined 2.7 to 3.5 million pounds from 1958 to 2016, and this decline has been attributed to climate change.
Invasive, predaceous lion fish thrive in warmer ocean temperatures and are increasing their consumption of native fish species and also their rates of reproduction. It is estimated that by 2115, the waters around the Keys will be so warm that 90% of the present species that reside there will no longer be able to survive there.
Karina brevis bloom off of Flordia (NOTE: a red tide does not have to be red!), Florida Fish and Wildlife C., Flickr
Rising temperatures also increase the risk of Harmful Algae Blooms (HAB’s) (“red tides,” etc.) which cause oxygen levels of the coastal waters to plummet leading to widespread death of fish and shellfish. Rising temperatures also stress corals and can cause them to eject their vital, mutualistic algae (a process know as “bleaching”). Bleaching in Florida’s Coral Reef was first seen in 1973, and there have subsequently been a number of severe, mass bleaching events (in 1987, 1997 and 2014). It is feared that, with the stress of rising temperatures, bleaching could become an annual, fall and winter event.
Rising levels of atmospheric carbon dioxide have also led to increases of carbon dioxide in the oceans. It is estimated that thirty percent of the human-generated carbon dioxide released through the burning of fossil fuels has ended up in the ocean. Much of this carbon dioxide reacts with water to form carbonic acid (CO2 + H2O –> H2CO3). Rising levels of carbonic acid has led to acidification of the ocean waters which in turn inhibits the formation of the calcium carbonate supporting structures of coral. It may also be causing existing calcium carbonate in coral to dissolve which further stresses the coral and may be leading to the structural weakening of the coral reefs themselves.
The acid-stressed corals are subject to a wide range of diseases including “stony coral tissue loss disease” (SCTLD). First observed in Florida in 2014, SCTLD has caused the death of 50% of the coral species found in Florida leading to further destruction of the established reefs.
Red tide. Photo by NOAA, Public Domain
Warmer ocean waters will lead to (and have already led to) more frequent, increasingly severe and more rapidly developing tropical storms and hurricanes. The impacts of the waves, winds and storm surges of these storms on the low-lying islets of the Keys could be devastating.
Another consideration of rising sea levels is the influence of the long, off-shore Florida Reef on incoming currents and wave energies. The Florida Reef is currently high enough to absorb a great deal of this incoming energy and can keep the wave action from reaching or harming the Atlantic coastal regions of the Keys. If sea levels rise, the barrier function of the Florida Reef will be reduced and more and more potentially destructive waves will strike the eastern sides of the Keys.
So the Keys are sitting out there exposed on all sides to forces that could destroy its ecosystems and tear about its very structural foundation. It is a paradise on the razor’s edge of great peril.
So what is being done about this pending catastrophe? Not nearly enough. An article by O. Milman in The Guardian (June 24, 2021) (“The Water is Coming: Florida Keys Faces Stark Reality as Sea Rises”) described a public meeting in the town of Marathon in the Keys at which county officials met with citizens to decide on a course of action. A number of the residents and officials refused to acknowledge that climate change and sea level rise were real. Others described their experiences with regular sea water intrusions and flooding in their homes and into the streets around them. The county officials agreed to back a plan to spend $1.8 billion dollars over the next 25 years to raise 150 miles of roads and install drains and pumping stations to remove the encroaching sea water. The only problem with this plan is that there is no money to pay for it!
The porous nature of the underlying limestone of the Keys is one reason why sea water so regularly floods areas of the Keys. Sea water intrudes through the limestone and reaches into areas well away from shores. There doesn’t have to be a tropical storm or a hurricane to push sea water onto the surface of the Keys either. A high tide can be sufficient to cause extensive flooding.
Coconut palms. Photo by M. Hamilton
Can the Keys be saved? Is there enough money and sufficient technology to save them? Is there sufficient political will to do anything constructive? Or, will we watch this incredible paradise fade away, as T. S. Elliot wrote in The Wasteland: “… not with a bang but a whimper.”