Earth’s largest ecosystem is collapsing: Over the past 13 months, average daily temperatures across most of the ocean surface have been the highest on record.
It is Data collected by the National Oceanic and Atmospheric Administrationor NOAA. Last year, scientists described this early phase as the first time Earth’s oceans had ever heated up like a “hot tub.”
“And now we’re ahead of last year,” says Robert West, a meteorologist with NOAA in Miami, Fla. And it’s not over yet, he adds: “We’re still breaking records.”
El Niño weather events contribute to rising ocean temperatures. This weather phenomenon occurs periodically when warmth spreads over the tropical Pacific Ocean’s surface waters. El Niño events occur every few years. The most recent one began in late spring of 2023.
But natural climate cycles can’t explain all of the warming. Heat is stored within 2 kilometers (1.3 miles) of the ocean’s surface. This heat storage has been building up for decades, says NOAA oceanographer Hosmay Lopez in Miami. And the rate at which the upper ocean is warming is accelerating, he adds.
Why? Since 1971, the oceans have absorbed more than 90% of the excess heat that greenhouse gases have trapped in Earth’s atmosphere. 380 Zettajoules of heatThat’s a lot. About 1.5 a million Twice the energy released two years ago During the eruption of Hunga Tonga Hunga Ha’apai volcanoIt is also twenty five a billion Twice the energy [equivalent to the energy released by the atomic bomb dropped on Hiroshima, Japan in 1945.
Releasing a large amount of heat into the ocean leads to various consequences. Let’s take a look at some of them.
Is the Atlantic hurricane season getting more active?
Hurricanes thrive on the moisture and heat that are churned up from the ocean. Currently, the Atlantic Ocean is very warm, so a very active hurricane season is expected.
On April 4, researchers at Colorado State University, Fort Collins released their 2024 outlook for the hurricane season. The prediction includes naming the largest hurricanes. 23 named storms are expected to occur this season, with at least 5 likely to be classified as Category 3 or above. Such storms have sustained winds of at least 179-208 kilometers per hour (111-129 miles per hour), and there is a 62% chance of a major hurricane hitting the U.S.
Researchers at the University of Pennsylvania released their own forecast three weeks later, predicting about 33 named storms for this season.
Most hurricanes form in the Atlantic Ocean between the Caribbean and West Africa. The sea surface temperature in this so-called Main Development Region (MDR) is extremely high, currently 1.5 degrees (2.7 degrees Fahrenheit) above normal, according to NOAA data.
West says the MDR surface hasn’t been this warm for only 10 months since 1981. “Eight of those months have occurred this year, except for April 2024,” he said.
La Niña is the opposite of El Niño. It occurs when much of the tropical Pacific’s surface water becomes relatively cold. The likelihood of La Niña occurrences affects new hurricane forecasts. Why? Winds over the Atlantic Ocean tend to disrupt developing hurricanes. During La Niña, these winds weaken, increasing the likelihood of hurricane formation.
As of April 11, NOAA stated that the probability of a La Niña occurring from August to October is 80%. This is the peak of hurricane season.
“Just one landfalling hurricane can make for an active season,” the Colorado report stated.
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Coral reefs around the world are bleaching
The sweltering seas could put coral reefs around the world in danger. These living structures support about a quarter of known marine species.
When corals are stressed by heat, they expel the colorful algae living in their tissues. These symbiotic algae, which perform photosynthesis, typically provide food for the corals. But when the algae are expelled, the corals’ white skeleton is exposed. This is known as coral bleaching, and it can be deadly for the corals.
Since early 2023, coral bleaching events have been occurring on a global scale. In fact, on April 15, NOAA officially announced that the situation qualifies as a global-scale coral bleaching event. This is only the fourth time such an event has occurred since the large-scale bleaching events of the 1980s.
“From February 2023 to April 2024, significant coral bleaching events have been documented in major hemispheric regions,” notes Derek Manzelo, a NOAA coral reef ecologist working at the College Park, Maryland.
How many corals will die from this phenomenon won’t be known until months or years after it’s over, says marine ecologist Carly Kenkel at the University of Southern California in Los Angeles. “It’s the worst bleaching event we’ve ever seen in the Caribbean, and it definitely seems that way for the Great Barrier Reef too. [off Australia] Just like that.”
Antarctic sea ice hits record low
The Southern Ocean is absorbing almost as much heat as it is from human-induced climate change. The combined Atlantic, Pacific, and Indian Oceans. One reason for this is the strong winds circulating over the Antarctic Ocean, which constantly pull cooler, heat-rejecting water to the surface. As a result of absorbing all that heat, over the past year, Antarctic sea ice is getting worse.
Antarctic sea ice typically falls to its annual minimum in February, bottoming out at about 3 million square kilometers (1.2 million square miles), according to the National Snow and Ice Data Center in Boulder, Colorado. This February, the ice fell even further to just 2 million square kilometers, tying the second-lowest annual minimum on record. Just five months earlier, the minimum had been 2 million square kilometers. maximum The region’s ice extent this year has reached a record low of about 17 million square kilometers (6.6 million square miles).
Warming oceans and changing air currents probably caused these cyclones, says Monica Ionita, a climatologist at the Alfred Wegner Institute Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany. “It was just too warm, both above and below the ice,” she says.
Antarctic sea ice had remained fairly stable since the 1980s, but around 2015, that all changed.
Suddenly, the surface temperature of the Southern Ocean has started to rise, and now we’ve had three consecutive summers where Antarctic sea ice has reached record lows, leading some researchers to worry that low Antarctic sea ice levels could become the new normal.
Why do we care? Because when the ice melts, the excess water has to go somewhere, and that somewhere will eventually end up on land, where it can flood coastal areas around the world.
Ionita says the data seems to indicate that Antarctic sea ice is permanently shrinking, but it would be helpful to have more than 40 years of satellite data on this to be sure.
On the other side of the planet, Arctic sea ice has been steadily declining—by about 12 percent every decade. But in recent years, the sea ice hasn’t set new record lows. Ionita speculates that this may be because the Arctic has already settled into its own new normal.
If a similar transition is underway in Antarctica, she said, it could mean a temporary plateau in sea ice loss. “We’ll just have to wait and see.”
For now, scientists don’t know when sea surface temperature records will stop being broken.
Lopez says La Niña weather can cool ocean temperatures, but ocean temperatures continued to break records during the 2020-2023 La Niña event. West says this shows that even if the equatorial Pacific cools, “it doesn’t necessarily stop records being broken everywhere.”
Source: www.snexplores.org
