When Americans flock to the beach this summer, they’re often greeted with unsettling news: Their destination may smell like dead fish or rotting seaweed — and the danger often lurks from the water. offshore currents or even shark attacks.
In a warming world, those problems will get worse, experts say.
“The climate is changing and it is changing drastically,” said Todd Crowl, director of the Environmental Institute at Florida International University in Miami. “It’s measurable and happening.”
Not a single day of beach destruction has been directly attributed to a warming globe. But increases in both atmospheric and ocean temperatures are rapidly changing the coastlines where land and water meet.
The most obvious impact is rising sea levels, which over the years will erode beaches, threaten coastal homes and the marshes that line the coastline. But some of the effects of climate change are less obvious and are starting to manifest now.
This year could be a sign of even more extreme events, destroying the coast. The National Oceanic and Atmospheric Administration announced Wednesday that global ocean temperatures hit a record high in May, the second consecutive month of record-breaking ocean temperatures. National Oceanic and Atmospheric Administration speak.
Here are just a few ways ocean warming could affect US beaches
smelly dead fish
What is happening? Thousands of dead fish have recently washed ashore in Texas, creating a foul-smelling mess on some beaches.
The same thing happened in Louisiana last June when the temperature soars and storms cause a “violent fish death”, according to the state Department of Wildlife and Fisheries. Florida had a big event of 2020 kills tens of thousands of fish in Biscayne Bay.
“The oxygen drops to zero, everything dies,” says Crowl. “Sadly, we have a segment where there are 20 or 30 rays swimming upside down trying to gasp.”
Such die-off can lead to water systems being restored once temperatures return to normal, adding nutrients to the water and bottom. But when they do, they make beaches smelly and unattractive. In Texas, officials warned people not to get into the water because of the bacteria and sharp fins on rotting fish.
Why does it happen? Warmer water holds less oxygen. When water temperatures rise above 70 degrees, Texas fish, mainly menhaden, have a hard time getting enough oxygen to survive, Quintana Beach County Park officials said.
Is climate change to blame? Heat-related fish deaths have long been common in shallow coastal areas, but the worry is that as the overall ocean temperature rises, they will become more common.
Crowl said of Florida: “We haven’t seen a single fish kill in 20 years and now we’ve seen three in three years.
Rising water temperatures due to climate change could worsen hypoxia in locations across the United States, which are prone to deficiency, say NOAA’s National Oceanic Administration experts. oxygen and in extreme cases, fish die due to extremely low oxygen levels.
There is also a negative feedback loop involved because fish are endothermic, meaning they have the same temperature as the water they are swimming in. As the water warms, their metabolism increases, which increases their need for oxygen, said Andre Boustany, global scientist. director at the Monterey Bay Aquarium in Monterey, California.
Seaweed stinks more
What is happening? Florida beachgoers are dealing with thick sheets of rotting brown seaweed as a giant swath of sargassum drifts westward and piles up on white sand beaches.
“You’re basically swimming through kelp rafts,” said Kevin Boswell, director of the marine biology program at Florida International University. “Itching and scratching, it’s like swimming through a bush.”
Sargassum, a naturally occurring macroalgae, has been growing at an alarming rate this winter. The ocean belt where it occurs naturally stretches across the Atlantic Ocean from Africa to Florida and the Yucatan Peninsula and is up to 200 to 300 miles wide.
Seaweed mats grow larger when they have more nutrients, which they get when dust is blown into the sea from the Sahara in Africa. These carry iron and fertilized phosphorus into the water, allowing mats to grow.
Is climate change to blame? The more frequent occurrence of these seaweed spots along the US coast could be due to a variety of factors, including climate change, the scientists say. But warmer ocean temperatures stimulate the growth of seaweed blobs.
“It always comes in some amount on the Florida coast,“But this is completely new,” said Arlo Hemphill, project lead on marine reserves with Greenpeace. You can get a foot of sargassum, which is quickly cleaned. What we’re talking about now isn’t a foot, it’s many feet tall. It’s completely unmanageable.”
Could climate change make it worse? As the atmosphere warms, it adds more energy to the global environment, because heat = energy.
“With climate change and global temperatures increasing, you’re putting more energy into the environment. One of the ways that energy can be released is by enhancing wave formation. Waves are just one of them. other forms of energy, they’re kinetic,” says Boustany.
Rising land temperature also increases wind, thereby increasing waves. Both contribute to offshore currents, which are the result of wave energy.
NOAA is working on this but so far the results are uncertain. Offshore currents are known to be mainly caused by beach breaking waves and tend to occur more frequently and more strongly with larger waves.
There has been some research showing that climate change may increase wave heights in some locations. NOAA experts told USA TODAY that if wave heights increase, so can the frequency and intensity of offshore currents.
Sharks on the move
What is happening? Sharks appear more in areas inhabited by humans. Partly because shark populations are growing due to decades of conservation, but also because the prey they eat, including fish, seals, sea lions and squidis moving as ocean temperatures warm.
In some cases, these changes are changing the shark’s migration patterns, putting them in more contact with humans in the water. Researching this is one of NOAA’s priorities.
Shark attacks are still rare and appear to be occurring steadily, but sightings of a 10-foot great white shark are still enough to clear beaches and make even the most avid swimmers Can’t get out of the water either.
Where is it happening? Boustany said anywhere there is unusually warm ocean water, but scientists are seeing it especially on the West Coast.
Is climate change to blame? Climate change that is warming the oceans is driving this behavior like the sharks, an apex predator, following their prey.
More red tide
What is happening? Red tide is the common name for what scientists call harmful algal blooms. They occur when populations of plant-like organisms called algae grow out of control. Some may produce toxic or harmful effects on humans, fish, marine mammals, and birds. The name “red tide” comes about because some forms of water turn red.
“They’re happening more and more often, and they’re happening in places where they really haven’t happened before,” Crowl said.
Is climate change to blame? While Texas and Florida’s Gulf Coast have always experienced such tides, they are now starting to occur in the Florida Keys and beaches near Miami, says Crowl.
“We just launched a major project with NOAA to build red tide early warning sensors so we can warn people before they become dangerous,” he said. “They can cause breathing problems in children so we have to issue warnings not to swim at this beach or that beach in their presence.”
Beaches are disappearing
What is happening? Rising sea levels and increasingly violent storms are predicted to eventually engulf many of the world’s beaches, but that won’t happen for decades. However, some areas are already starting to see the effects of higher sea levels.
“Sea-level rise is something we’ve been measuring for 100 years,” says Crowl. “It’s not a prediction, it’s not a guess. That’s reality.”
As a result, there are days in Florida with full moons, high tides, and westerly winds when some beaches literally disappear because the water rises all the way to the dunes, Crowl said from St. Augustine, along the north Atlantic coast of Florida.
Is climate change to blame? A study published in 2020 predicts that half of the world’s beaches could disappear in the next 75 years due to climate change. A 2023 study found that 70% of California’s beaches could be threatened.
“We’ve seen times when you can’t go to the beach unless you’re willing to wade – and our beach is 75 feet wide at low tide,” says Crowl.