Climate Change Watch: KB’s ocean temperatures are somewhat back to normal this summer. Why?

Key Biscayne’s ocean waters went from feeling like bathwater the last two summers to a touch cooler — a reminder of the ocean’s chaotic dance with a world that is getting warmer every year. 

The hottest recorded ocean temperature off Key Biscayne was on July 19, 2023, at a whopping 90.86 degrees. Great swaths of coral cooked and died in a mass bleaching event. This week, those very same waters are hovering around 85 degrees – not exactly refreshing, but not lethal either.

The reason is that there has been a slight pattern change from last summer, said Will Redman, a meteorologist at the National Weather Service. “We went from being in La Niña last summer to being in a more neutral state now,” he said. 

La Niña is a climate pattern that affects sea surface temperatures in the central and eastern tropical Pacific Ocean.

The more normal ocean temperatures don’t mean the U.S. is getting a reprieve from climate change this summer.

The U.S. has already experienced record-breaking heat temperatures this summer, particularly in the Midwest and the Northeast. Right now, Europe is experiencing a heat wave. Last year was the warmest year in global temperatures ever recorded since 1850, according to data.

Still, the ocean water did not follow suit and heat up to exceedingly high temperatures. This is because water has a high specific heat capacity, meaning that it can absorb a large amount of heat without a significant temperature change, Redman said.

The ocean requires a lot of energy to warm up and is not always affected by a brief heatwave, the meteorologist explained. 

Scientists predict that heat waves within the ocean are expected to become more frequent in the coming years. 

“The notion is that with a planet that is increasing in temperature over time, the likelihood of heat wave events occurring also increases,” said Enrique Montes, an associate scientist within the National Oceanic and Atmospheric Administration in Miami.   

Basically, the ocean experienced a heat wave in 2023 and somewhat in 2024.

Montes said there is a very strong relationship between water temperature and how the ecosystem responds to those conditions. “For example, with warmer temperatures, there is more microbial activity. That is the growth of bad bacteria,” he said. 

With this bad bacteria, there are more ways for it to cause harm to different organisms within the water, as well as humans. “These can be in a place like Biscayne Bay where you have such influence from runoff and sewage,” Montes said.

Along with the rate of global warming, sea level rise also continues to accelerate. 

According to NOAA, the global average sea level has risen 8-9 inches since 1880, with the onset of the industrial age, and “high tide flooding is now 300% to more than 900% more frequent than it was 50 years ago.” 

All of this is happening as President Donald Trump’s administration has made budget cuts to NOAA and the National Weather Service. NOAA has stated that it will “discontinue ingesting, processing, and distributing” all Defense Meteorological Satellite Program (DMSP) data by June 30, 2025. 

The satellites “provide the military with important environmental information used in planning and conducting U.S. military operations worldwide and important weather data used to increase the timeliness and accuracy of weather forecasts around the globe.” 

Trump has said on more than one occasion that climate change is a hoax.