When you think about the risks that climate change poses to Florida, you probably picture a rising sea swallowing Miami Beach and hurricanes battering the coast.
You might not imagine “guacamole-thick” toxic algae strangling the state’s waterways and polluting its beaches. But that’s exactly what several Florida counties have been experiencing since late June, after the Army Corps of Engineers spent months siphoning off nutrient-rich water from Lake Okeechobee to preserve a leaky, problem-prone dike.
Meanwhile, experts warn that we’ll only see more of these dangerous blue-green algae blooms as global temperatures rise—in Florida and nationwide.
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“These types of blooms are going to be more prevalent as the climate warms,” said Rob Moore, senior policy analyst for the Natural Resources Defense Council (NRDC) water program. “That’s yet another motivating factor for the U.S. and for governments around the world to take rapid action to decrease emissions that are causing climate change.”
The thick muck that is currently strangling Florida’s Treasure Coast, closing beaches and clearing out hotel reservations during the busy summer season, is the result of a perfect storm of exacerbating factors. Cyanobacteria blooms tend to form in warm water that has been polluted with nutrients like phosphorus and nitrogen, found in fertilizers. That pollution is facilitated by rainfall and the resulting runoff. It’s no surprise, then, that a blue-green algae bloom would occur in South Florida after heavy rains caused Lake Okeechobee to rise nine inches right before the hottest June on record in the contiguous U.S., according to statistics from the National Oceanic and Atmospheric Administration (NOAA). In fact, South Florida witnessed above average temperatures for “almost the entire month,” according to a report from the National Weather Service and the NOAA, with “a strong southwest wind” keeping the cooler Atlantic breeze at bay mid-month.
“When you have elevated temperatures in the summer, and when you have a lot of rain—which Florida has been getting this summer—you’ve got the perfect conditions for cyanobacteria,” said Moore. “And those conditions are going to exist far more frequently as the climate warms.”
There is no data tracking the nationwide frequency of blue-green algae blooms but Moore says that several bodies of water are “experiencing these types of problems much more frequently than they did in the past.”
Lake Erie, for example, has been dealing with harmful cyanobacteria blooms for years, sometimes interrupting drinking water access for thousands of people. The NOAA is predicting more toxic blooms to come for Lake Erie in 2016. And as recently as this Tuesday, two beaches in Vermont had to close because of the toxic algae, which sickens swimmers on contact.
These incidents and many others have led the Environmental Protection Agency (EPA) to warn that climate change “might cause harmful algal blooms to occur more often, in more water bodies and to be more intense.”
As the EPA notes, climate change doesn’t just facilitate the spread of blue-green algae blooms by warming the waters in which they reproduce; warming temperatures also give rise to the conditions in which they initially form.
Sea level rise, for example, will create more shallow coastal water, providing an ideal environment for cyanobacteria to flourish. Higher levels of carbon dioxide in the air will feed the algal blooms. And changes in rainfall patterns caused by climate change could bring even more nutrients into the waterways.
“Climate change tends to skew our rainfall toward larger, less frequent events,” Moore told The Daily Beast. “And those are the types of events that really flush a lot of phosphorus and nitrogen off of the land and into the water.”
In recent years, more of our rain has indeed come in larger and more concentrated doses. According to NOAA data, extreme one-day precipitation events have been on the rise, with eight of the top 10 years for these events occurring since 1990—a trend that many scientists have connected to rising temperatures.
Between the rising temperatures and the heavy rains, Moore warns, “it will take less nutrients to produce the same types of blooms in the future.”The nutrients causing the current blue-green algae bloom in Florida are the result of “decades of pollution,” as the Sun Sentinel reported last week, from surrounding cattle ranches, farms, citrus groves, and suburban neighborhoods. And while the Army Corps of Engineers tries to keep the current South Florida bloom in check, there’s no guarantee that it won’t return.
Some consequences of climate change, like sea level rise, have been extensively modeled—but not the conditions for blue-green algae blooms.
“It’s a very difficult problem to forecast,” said Moore. “There are several different species of blue-green algae and each one of them grows preferentially based on the available nutrients and the available temperature and sunlight.”
“You might get one species of cyanobacteria dominating one year, you might get another species dominating another year,” he continued. “And you might get totally different species causing a bloom in different parts of the country.”
Short of reducing water pollution or mitigating the effects of climate change, the toxic guacamole-like sludge will keep coming back. It is one of the least predictable effects of rising global temperatures and, perhaps, the most disgusting.
