Several heat waves across the globe have sent temperatures soaring to new records over the past few weeks. From China and Europe to right here in the United States, record high temperatures are being rewritten day after day.

But another heatwave is catching the eyes of scientists, creating fear that cascading effects from our warming oceans could have major detriments to not only our ecosystem, but our economy as well.

What You Need To Know

  • An unprecedented marine heatwave is sending water temperatures soaring over 5 degrees above average.

  • Marine heat waves are prolonged periods of high sea surface temperatures caused by weakened wind patterns.

  • Impacts on marine ecosystems include coral bleaching, species migration and harmful algal blooms.

  • Economic impacts also are common, including effects to fisheries, aquaculture and tourism.

Since April, the National Oceanic and Atmospheric Administration has been monitoring a steady climb in sea surface temperatures across the Caribbean Sea and the surrounding waters across Florida, the Gulf of Mexico and the Bahamas.

These waters have warmed significantly in recent weeks, surpassing records in many spots. As a result, waters have climbed to between 1.8 degrees to 5.4 degrees warmer than normal. Florida water temperature records date back to 1981.

On Monday, July 24, a water sensor located five feet underwater at Manatee Bay, Fla. reached 101.1 degrees. The previously accepted global record for sea surface temperature was 99.7 degrees in the Persian Gulf, set a few years back.

This temperature will need to be certified by several agencies before being deemed an official measurement for the warmest waters ever found on Earth. And there’s some skepticism about if this would even qualify. 

That’s because the sensor is in an area of very shallow and murky water. As a result, the water absorbs the sun’s radiation exceptionally well - more so than an observation in a deeper, more clear site.

However, regardless if this gets certified or not, several other stations in the same area registered temperatures in the upper 90s, including Murray Key, which registered a reliable temperature of 99.3 degrees - just 0.3 degrees shy of the global record. 

You can view those water temperatures by visiting NOAA’s Physical Sciences Laboratory map room here and you can view specific water temperatures by buoys here.

So how do marine heat waves form?

A marine heatwave refers to an extended period of anomalously high sea surface temperatures (SSTs) in a particular region of the ocean. These heat waves can have significant effects on marine ecosystems and human activities.

Marine heat waves typically develop because of a combination of atmospheric and oceanic processes. One common cause is the weakening of winds that usually promote the upwelling of cold, nutrient-rich waters from the ocean depths.

Without this upwelling, warm surface waters persist, leading to elevated SSTs. Climate change can contribute to the intensification and frequency of marine heat waves by raising overall ocean temperatures.

In recent weeks, high pressure in the Atlantic coupled with high pressure in the Gulf have led to persistent southwest flow through the state. This has also provided a pocket of very calm winds across the Florida Keys, allowing these sea surface temperatures to skyrocket.

Long-term weather models suggest this pattern may continue over the next two months, allowing for more opportunities to increase the local water temperatures.

What are some of the impacts we can see?

Marine heat waves can have far-reaching impacts to an area, not only in the waters but also for day-to-day activities for those who live in the area. These heat waves can also cause a slew of socioeconomic impacts to a larger region.

When it comes to a marine ecosystem, the devastation can be extensive. As the waters warm, it can lead to the bleaching and mortality of corals, which form the foundation of vital reef ecosystems.

Unfortunately, NOAA has issued an Alert Level 2 - the highest alert possible - for coral bleaching across the Florida coastline. This forecast calls for more widespread bleaching of corals as far north as Central Florida by late August.

Current coral population estimates, according to researchers at the University of Miami, sit at around 5% across our southern waters. But data from those same researchers say that by the end of this year, if this forecast were to verify, coral across Florida’s coast could reach near 0%. 

On top of coral bleaching, including fish, shellfish and plankton, have specific temperature tolerances and may be forced to migrate to find suitable conditions or face population declines. This disruption can have cascading effects on the food web, affecting predator-prey relationships and ecosystem dynamics.

Marine heat waves can also lead to the proliferation of harmful algal blooms, which can produce toxins harmful to marine life and humans. This poses risks to fisheries, aquaculture, and coastal economies that rely on a healthy marine environment.

Additionally, loss of fisheries’ productivity can affect global seafood supplies and exacerbate food security challenges in vulnerable regions.

Human day-to-day activities are affected in various ways during marine heat waves. Coastal communities may experience more frequent and severe weather events like hurricanes and tropical storms, which can cause significant damage to infrastructure and disrupt lives.

Reduced fishing yields can lead to economic losses for fishers and related industries, affecting livelihoods and coastal economies. Losing tourism revenue because of damaged or bleached coral reefs can affect local economies and employment opportunities in coastal areas.

A large shipment of lobsters look at the camera (AP Photo)
A large shipment of lobsters look at the camera (AP Photo)

Socially, marine heat waves can lead to forced migration of communities that rely heavily on marine resources for their sustenance and culture. This can result in social upheaval and increased pressure on resources in new areas of settlement.

Disruptions in marine ecosystems can affect recreational activities such as boating, diving and beach going, which are crucial for coastal tourism.

Bottom Line - the Earth’s oceans are warming at an alarming rate never seen before, and that’s none more evident than in Florida. If some of these forecasts verify in the coming months, we could be on the verge of historic impacts to both the local ecosystem as well as the nation’s economy.

The effects of this warming water will be far-reaching, and are hard to predict how disastrous they might be. If we don’t curve warming globally, and fast, these marine heat waves will only continue to happen in the years and decades to come.

Our team of meteorologists dives deep into the science of weather and breaks down timely weather data and information. To view more weather and climate stories, check out our weather blogs section.