Ocean-related tourism and recreation supports more than 320,000 jobs and $13.5 billion in goods and services in Florida. But swimming in the ocean became much less appealing in the summer of 2023, when water temperatures off Miami reached 37.8 degrees Celsius (101 degrees Fahrenheit).
The future of some jobs and businesses in the ocean economy has also become less secure as the ocean warms and damage from storms, rising sea levels and marine heat waves increases.
Ocean temperatures have been warming up over the last century, and reaching records for much of last year, driven primarily by rising greenhouse gas emissions resulting from the burning of fossil fuels. Scientists estimate that more than 90% of excess heat produced by human activities has was taken by the ocean.
This warming, hidden for years in data of interest only to oceanographers, is now having profound consequences for coastal economies around the world.
Understanding the role of the ocean in the economy is something I’ve been working for over 40 years, currently in Center for the Blue Economy from the Middlebury Institute of International Studies. Mostly, I study the positive contributions of the ocean, but this has started to change, sometimes dramatically. Climate change has made the ocean a threat to the economy in many ways.
The dangers of rising sea levels
One of the biggest threats to economies arising from warming oceans is rising sea levels. As water heats up, it expands. Along with the melting of glaciers and ice sheets, the thermal expansion of water has increased flooding in low-lying coastal areas and put the future of island nations at risk.
In the US, rising sea levels will soon overwhelm Jean Charles Island in Louisiana and Tangier Island in the Chesapeake Bay.
Flooding during high tide, even on sunny days, is becoming increasingly common in places like Miami beach; Annapolis, Maryland; Norfolk, Virginia; and San Francisco. High tide flooding has more than doubled since 2000 and is on track to triple by 2050 along the country’s coast.
Sea level rise also pushes salt water in freshwater aquifers, from where water is extracted to support agriculture. The strawberry harvest on the California coast is is already being affected.
These effects are still small and highly localized. Much greater effects occur with storms intensified by sea level.
Higher sea levels could worsen storm damage
Warmer ocean water fuels tropical storms. It’s one of the reasons meteorologists are warning about a busy 2024 hurricane season.
Tropical storms capture moisture from warm water and transfer it to cooler areas. The warmer the water, the faster the storm can form, the faster it can intensify, and the more longer it can lastresulting in destructive storms and heavy rains that can flood cities even far from the coast.
When these storms now reach the already higher sea level, the waves and storm can dramatically increase the coast inundation.
Tropical cyclones caused more than US$1.3 trillion in damages in the US between 1980 and 2023, with an average cost of $22.8 billion per storm. Much of this cost was absorbed by federal taxpayers.
These are not just tropical storms. Maine saw what could happen when a winter storm in January 2024 generated tides 5 feet above normal which filled the coastal streets with sea water.
What does this mean for the economy?
The possible future economic damage from sea level rise is not known because the pace and extent of sea level rise are unknown.
One estimate puts the costs arising from sea level rise and storms alone at more than $990 billion this century, with adaptation measures capable of reducing these costs by just US$100 billion. These estimates include direct damage to property and damage to infrastructure such as transportation, water systems and ports. Impacts on agriculture resulting from the intrusion of salt water into the aquifers that support agriculture.
Marine heat waves leave fishing in trouble
Rising ocean temperatures are also affecting marine life through extreme events, known as marine heatwaves, and more gradual, long-term temperature changes.
By spring 2024, one-third of the global oceans were experiencing hot flashes. The corals are fighting through their fourth global bleaching event It is recorded that high ocean temperatures cause them to expel the algae that live in their shells and give corals their color and provide food. Although corals sometimes recover from bleaching, about half of the world’s coral reefs have died since 1950, and its the future beyond the middle of this century is bleak.
Losing coral reefs is about more than their beauty. Coral reefs serve as nurseries and feeding areas for thousands of fish species. By NOAA’s estimate, about half of all federally managed fisheryincluding snapper and grouper, depend on reefs at some point in their life cycle.
Warmer waters cause fish to migrate to cooler areas. This is particularly notable in the case of species that like cold water, such as lobsters, which have constantly migrated north to escape warmer seas. The once-robust lobster fishery in southern New England significantly decreased.
In the Gulf of Alaska, rising temperatures nearly wiped out snow crabs, and a $270 million fishery had to be harvested. completely closed for two years. A big heat wave off the Pacific coast it spanned several years in the 2010s and disrupted fishing from Alaska to Oregon.
This won’t change soon
Heat accumulated in the oceans and greenhouse gases in the atmosphere will continue to affect ocean temperatures for centuries, even if countries reduce their greenhouse gas emissions to zero by 2050, as expected. So while the ocean temperatures fluctuate year to yearthe general trend is expected to continue upward for at least a century.
There is no cold water tap that we can simply turn on to quickly return ocean temperatures to “normal,” so communities will have to adapt as the entire planet works to reduce greenhouse gas emissions in order to protect ocean economies for the future.
This article was republished from The conversationan independent, nonprofit news organization that brings you facts and analysis to help you understand our complex world.
It was written by: Carlos Colgan, Middlebury Institute of International Studies.
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Charles Colgan receives funding from several sources, including NOAA and Lloyds of London. He authored the 5th chapter of the National Climate Assessment on oceans and the 4th chapter of the California Climate Assessment on coasts and oceans.
