By: Katelyn Holcomb

Florida’s Perfect Hot Tub: The Intersection of Law and Climate Change 

Florida’s coastline is celebrated for its pristine beaches, refreshing ocean water, and a diverse ecosystem of sea life. However, in July of 2023, Florida made the news in much graver circumstances.

Florida’s water temperatures usually average around 88 degrees Fahrenheit in the summer.[1] However, this July, scientists recorded temperatures at 101.1 degrees Fahrenheit in some areas like Manatee Bay near Everglades National Park.[2] According to Hot Spring Spas, the ideal temperature for a hot tub measures around 100 to 102 degrees Fahrenheit—making Florida’s ocean water the perfect jacuzzi.[3] This unprecedented spike in ocean temperature has climate and ocean scientists alarmed, and you should be, too.

The Ocean’s Rising Heat Content

The ocean can absorb immense amounts of heat without substantial increases in temperature, making it the largest solar energy collector on Earth.[4] Sunlight is the main source of ocean heat; as sunlight reaches Earth’s surface, the ocean absorbs some of its energy.[5] The currents and tides then spread the heat from the surface of the ocean to deeper waters around the globe.[6] Because about 70% of the surface of the Earth is covered by the ocean, they have been acting as a vast heat reservoir.[7] If the ocean absorbs more heat than it releases over a given time span, its heat content increases.[8] Since modern record keeping began in 1955, 90% of global warming has occurred in the ocean.[9] We must ask ourselves: What are the long-term implications of our ocean’s heat content increasing?

A common principle in physics is thermal expansion.[10] Simplified, thermal expansion occurs when water temperature increases and atoms move, which causes the volume of water to increase.[11] Warming waters and thermal expansion have accounted for about half of the measured sea level rise.[12] However, rising sea levels are not the only consequences of our ocean’s rising temperature[13] Consequences of rising temperatures include accelerated melting of Earth’s ice sheets, changing ocean health and biochemistry, intensified weather phenomena, and widespread coral bleaching events.[14]

Devastating Impact on Coral Reefs and Marine Ecosystems

Coral reefs are home to a great amount of biodiversity. They also provide food resources, recreation opportunities, and costal protection through dispersal of wave energy.[15] However, corals are very sensitive organisms, and even small changes in temperature can cause reduced growth, reproduction problems, vulnerability to diseases, bleaching, and even death.[16]

Naturally, the impact of the scorching water temperatures in Florida was felt almost immediately. On August 17, 2023, the National Oceanic and Atmospheric Administration (NOAA) briefed the public on how the record-breaking warm ocean temperatures stressed, bleached, and in some cases, killed coral within 3,800 square miles of the Florida Keys National Marine Sanctuary.[17] According to the briefing, a large-scale coral bleaching event was underway, impacting two ocean basins and more than ten countries/states/territories. [18]

Zooxanthellae, an alga that lives within the coral, converts sunlight into energy to provide nutrients to corals. Bleaching occurs when Zooxanthellae releases harmful compounds due to temperature stress, resulting in the coral expelling the colorful Zooxanthellae, which leaves the coral tissue white.[19] Bleached coral is not necessarily dead coral; some coral reefs have fully recovered after bleaching events.[20] However, if the Zooxanthellae does not return to the coral, the coral will eventually die from starvation.[21]

It is well established that bleaching is a natural event that precedes atmospheric warming due to climate change.[22] Some argue that most coral reefs face imminent death from bleaching, while others claim bleaching is a natural and adaptive process.[23] Despite the debate, one thing is undeniably true—stressed reefs have a heightened sensitivity to temperature change and are less likely to recover from a bleaching event.[24] Dr. Derek Manzello, coordinator of the NOAA’s Coral Reef Watch Program, pointed out that the high temperatures, like those recorded in Florida, “have always been inhospitable for corals, even before climate change.”[25] Over half of Earth’s coral reefs have already been lost and are considered the species group with the most rapid increase in extinction risk.[26] Scientist are attempting various methods to restore Florida’s coral reef, but it is truly a race against time. Coral reefs in Florida and around the world are in jeopardy unless we intensify our efforts to protect them.

Current Policies and Moving Forward

There are several statutes, such as the Coral Reef Conservation Act and the National Marine Sanctuary Act, and organizations like the Coral Reef Task Force, International Coral Reef Initiative, and the Coral Reef Evaluation and Monitoring Project (CREMP), that serve to protect, conserve, and restore coral reefs.[27] However, these statutes and organizations place far too much emphasis on monitoring and far too little emphasis on actively abating threats. For example, CREMP monitors corals along Florida’s coral reef, and every active CREMP monitoring site has a temperature logger. By closely monitoring water temperature, scientists can determine when temperature causes coral death and stress.[28] The data that has been collected has shown that both hot and cold-water temperature stress events are increasing.[29] While it is incredibly beneficial to know and understand this data, what is actively being done to help prevent our ocean’s heat content from increasing and  reduce wide-spread coral bleaching events?

As of 2015, when all 196 Parties to the UN Framework Convention on Climate Change adopted The Paris Agreement, the goal has been to limit global temperature rise to below 2 degrees Celsius.[30] However, given the grave risks, we generally strive for 1.5 degrees Celsius.[31] However, a distributed hydrological model study, providing a comprehensive global analysis of bleaching under different levels of global warming, suggests that most coral reefs will experience extensive degradation at the current goal.[32] The study concluded that, in order to protect at least half of the coral reef cells, global mean temperature change must be limited to 1.2 degrees Celsius.[33] The Paris Agreement’s goal to limit global temperature is not nearly as aggressive and audacious as what is required to protect our ocean’s corals

Our policies and laws going forward should ambitiously focus on limiting global temperature rise to around 1.2 degrees Celsius. It is difficult to comprehend the gravity of rising ocean temperatures, but the window to save our oceans and coral reefs is small and rapidly closing. Broader international involvement to promptly change worldwide environmental policies and laws is necessary to reduce the impact that global warming has on our oceans and coral reefs.

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[1] Jenny Staletovich, Climate Scientists Are Alarmed By Record Water Temperatures Off Florida’s Coast, NPR, (July 17, 2023, 5:10 AM).

[2] Joe Hernandez, With Florida Ocean Temperatures Topping 100, Experts Warn of Damage to Marine Life, NPR, (July 26, 2023, 12:57 PM), https://www.npr.org/2023/07/26/1190218132/florida-ocean-temperatures-101-marine-life-damage

[3] Hot Spring Spas, What Is The Ideal Hot Tub Temperature?(last visited Oct. 10, 2023).

[4] Rebecca Lindsey & Luann Dahlman, Climate Change: Ocean Heat Content, Climate.gov (Sept. 6, 2023), https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content#:~:text=The%20main%20source%20of%20ocean,latitudes%20and%20to%20deeper%20levels.

[5]  U.S. Env’t Prot. Agency, Technical Documentation: Ocean Heat 10, https://www.epa.gov/sites/default/files/2021-04/documents/ocean-heat_td.pdf

[6] Lindsey & Dahlman, supra note 4.

[7] Regents of U. Cali., The Ocean: A Giant Heat Reservoir, (2017), https://datalab.marine.rutgers.edu/wp-content/uploads/2019/06/W-Reading-Ocean-Giant-Heat-Reservoir.pdf

[8] Lindsey & Dahlman, supra note 4.

[9]  Ocean Warming, Nat’l Aeronautics and Space Admin. (2022), https://climate.nasa.gov/vital-signs/ocean-warming/

[10] Science and Tech: Thermal Expansion, Encyclopedia Britannica (Sept. 12, 2023).

[11] How Warming Water Causes Sea Level Rise, Jet Propulsion Lab’y, Cal. Inst. of Tech., https://www.jpl.nasa.gov/edu/learn/project/how-warming-water-causes-sea-level-rise/#:~:text=Thermal%20expansion%20happens%20when%20water,warming%20waters%20and%20thermal%20expansion.

[12] Id.

[13] United Nations, How Is Climate Change Impacting The Ocean, (last visited Oct. 11, 2023), https://www.un.org/en/climatechange/science/climate-issues/ocean-impacts

[14] Ocean Warming, supra note 9.

[15] Meixia Zhao et. al, The Status of Coral Reefs and Its Importance for Coastal Protection: A Case Study of Northeastern Hainan Island, South China Sea, Multidisciplinary Digit. Publ’g Institute (Aug. 12, 2019).

[16] Fla. Fish and Wildlife Conservation Comm’n, Long Term Temperature Monitoring, FWC (2022), https://myfwc.com/research/habitat/coral/cremp/tempmonitoring/#:~:text=Corals%20are%20highly%20sensitive%20to,to%20diseases%2C%20and%20even%20death.

[17] Nat’l Env’t Satellite, Data, and Info. Serv., Extreme Ocean Temperatures Are Affecting Florida’s Coral Reef, Nat’t Oceanic and Atmospheric Admin. (Aug. 18, 2023).

[18] Id.

[19] Florida Fish and Wildlife Conservation Comm’n, supra note 16.

[20] Tundi Agardy, America’s Coral Reefs: Awash With Problems, Issues In Science and Technology 20 (2004), https://issues.org/agardy-2/

[21] Fla. Fish and Wildlife Conservation Comm’n, supra note 16.

[22] Agardy, supra note 20.

[23] Id.

[24] Id.

[25]Nat’l Env’t Satellite, Data, and Info. Serv., supra note 17.

[26] Convention on Biological Diversity, Humanity at a Crossroads, Glob. Biodiversity Outlook 5 (Aug. 8, 2020).

[27] Coral Digest, Laws and Regulations About Coral Reefs, (last visited Oct. 10, 2023), https://www.coraldigest.org/index.php/ReefRegulations

[28] Fla. Fish and Wildlife Conservation Comm’n, supra note 16.

[29] Id.

[30] United Nations, UN Climate Change Conference Paris 2015, https://www.un.org/sustainabledevelopment/cop21/

[31] Id.

[32] K. Frieler et. al, Limiting Global Warming to 2 ◦C Is Unlikely to Save Most Coral Reefs, Nature Climate Change (Sept. 16, 2012).

[33] Id.