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Worldwide the average ocean temperatures have been in record-breaking territory for 15 months straight since last April. What's going on?
Why it matters: Abnormally hot ocean water helps fuel dangerous hurricanes. And when the water gets too hot, fish and other marine species also struggle to survive.
Why now: Climate change is broadly to blame, but there are other factors. Keep reading for four of the prime suspects.
The oceans are extremely warm right now. Worldwide, average ocean temperatures were in record-breaking territory for 15 months straight since last April.
That’s bad news on multiple fronts. Abnormally hot ocean water helps fuel dangerous hurricanes, like Hurricane Ernesto, which is expected to rapidly gain strength this week in the Atlantic, and like Hurricane Debby, which dumped massive amounts of rain along the East Coast of the U.S. last week. And when the water gets too hot, fish and other marine species also struggle to survive. For example, the ocean water near Florida is so warm that it’s threatening coral reefs.
So, why are the oceans so hot right now?
Let’s start with what we know: Climate change is broadly to blame. Humans continue to burn fossil fuels that release heat-trapping gasses into the atmosphere, and most of that extra heat is absorbed by the oceans. Ocean temperatures have been steadily rising for decades.
The cyclic climate pattern El Niño is also partly to blame. When El Niño is happening, there’s warmer water in part of the Pacific, and that generally means the Earth is slightly warmer overall. In 2023 and the first part of 2024, El Niño was happening and it caused global average temperatures to rise, including in the oceans.
“The two primary things are obviously global warming and El Niño,” says Andrew Dessler, a climate scientist at Texas A&M. But that’s where the certainty ends, because the oceans are even warmer than scientists expected from those two trends.
“Think of it like, the house was burglarized, and you have video of those two suspects doing it. And the question is: Is there somebody else helping them?” Dessler explains.
It seems like there probably was another suspect. And over the last 18 months or so, a few major theories have emerged about what it might be. Testing those theories is slow, laborious work for scientists, but after months of crunching the numbers, some early answers are emerging.
One reason that ocean temperatures started to spike last year is that ships stopped releasing so much pollution into the air.
In 2020, new international shipping regulations went into effect that required ships to use slightly cleaner types of fuel. The new fuel still releases planet-warming gasses like carbon dioxide, but it releases a lot less pollution into the air.
That’s good news for the overall health of humans and other animals – air pollution, particularly the sulfur-heavy pollution released by dirty shipping fuel, leads to serious illness. “This saves lives,” says Stephen Smith, an expert on air pollution and climate change at Pacific Northwest National Laboratory.
But all that pollution was also reflecting some of the sun’s heat, because sulfur helps clouds form and those bright, white clouds reflect sunlight. When the extra sulfur from ship pollution went away, scientists wondered if more of the sun’s heat would be absorbed by the oceans.
Teasing apart how much of an effect cleaner air over the oceans might have on ocean temperatures is surprisingly difficult. That’s because there are still lots of unanswered questions about how air pollutants affect clouds, which in turn reflect sunlight. “It’s a complicated system and it’s going to take some time to sort that out, but people are trying to do that,” says Smith.
The most cutting-edge research in the field does suggest ocean temperatures may have increased slightly in some parts of the world as sulfur pollution from ships decreased. In major shipping lanes where pollution from ships decreased significantly since 2020, there are fewer so-called ship tracks – long, thin clouds that form with the help of sulfur pollution, and look kind of like plane contrails – according to a new study published this week.
Without those reflective ship track clouds, more of the Sun’s energy does, indeed, seem to be making it to the surface of the ocean, where it is absorbed, the study finds. “This could be contributing to the warm temperatures we’ve seen in the last couple years,” says Andrew Gettelman, a climate scientist at Pacific Northwest National Laboratory and one of the authors of the forthcoming study.
The good news is that this type of warming, from cutting dangerous air pollution, isn’t caused by humans releasing new, additional greenhouse gas emissions. Humans already caused this warming, but weren’t feeling it because air pollution was protecting us.
When ocean temperatures started surprising scientists last year, one of the theories was that a massive volcanic eruption in 2022 might be partly to blame.
The Hunga Tonga-Hunga Ha'apai eruption happened off the coast of the Pacific island of Tonga. An underwater volcano erupted, sending sulfur, ash and water vapor into the atmosphere.
Usually, volcanic eruptions temporarily cool the Earth slightly, because the sulfur and ash in the atmosphere spread around the world and reflect extra heat from the sun.
But because the Hunga-Tonga eruption happened underwater, it spewed a lot of water vapor into the atmosphere as well. Unlike ash, water vapor absorbs heat from the sun. “Water is a greenhouse gas,” Dessler explains.
A handful of scientists publicly wondered if all that water vapor might be trapping extra heat, and contributing to off-the-charts ocean temperatures.
Recent research suggests that the answer is “No.”
“I was very skeptical of the warming effect,” says Dessler, who is an expert on how water vapor in the stratosphere affects the Earth’s climate. He points out that, despite the size of the eruption, it changed the total amount of water in the atmosphere very little. But, to know for sure, he and scientists at NASA had to analyze reams of data from satellites and other sources.
In July, they published a study showing there was no evidence that the eruption led to overall warming. If anything, like past eruptions, it contributed to slight cooling. “The bottom line is that this had a very tiny impact on the climate,” says Dessler.
But other scientific analyses about the potential role of the eruption on global temperatures are still underway, says Gavin Schmidt, a climate scientist at NASA who was not involved in the newly published study. “I’d caution against assuming that a single [research] paper will end up being the consensus,” he says.
Since the heat in the oceans originally comes from the sun, our local star is one place to look for answers about abnormal temperatures here on Earth.
The amount of energy coming from the sun changes a little bit over the course of an 11-year solar cycle. “As the sun’s output gets brighter and dimmer by about 0.1% over its 11-year cycle, the Earth’s global temperatures increase and then decrease by a little less than 0.1 degree [Celsius],” explains Gregory Kopp, a solar physicist at the University of Colorado, Boulder.
But that tenth of a degree Celsius change doesn’t account for the abnormally hot ocean temperatures of the last couple years. “The sun isn’t causing the recent record-breaking sea-surface temperatures,” Kopp says. The ocean is simply too large to immediately heat up or cool down in response to changes in the sun. “The sea contains so much heat energy that it doesn’t respond on the relatively short solar-cycle timescales,” Kopp explains .
So, in the quest to understand current record-breaking ocean temperatures, the sun doesn’t offer any answers.
The upshot is that scientists don’t know for sure what’s driving ocean temperatures into record-breaking territory. In addition to climate change and El Niño, cleaner air seems to be playing a role.
The last possibility is what Dessler calls “weirdness.”
The Earth’s climate is incredibly complex, and there’s some natural variability in temperatures on short time scales like one or two years. A few extra tenths of a degree of heat in the Atlantic due to nothing more but natural variability could account for a couple of record-breaking years, when it’s layered on top of warming from climate change and El Niño.
“My guess is, in the end, it’s just going to be internal variability,” Dessler explains. “Like, something weird happened! Because the climate’s always doing something weird.”
Gettelman agrees that normal year-to-year temperature variability is an important factor.
“We're going to see the planet warm in fits and starts,” he explains. For example, there was a period in the 2010s when the Earth didn’t warm very much. “People were saying ‘Oh, global warming's over,’” remembers Gettelman. “It wasn't. It was just a transient thing, and we now may be recovering from that.”
The real concern for climate scientists isn’t so much what happens to temperatures in a given year or two, but whether the overall warming trend is accelerating. If the oceans don’t cool off somewhat in the coming months, that would suggest that the Earth is heating up very quickly.
“I think people are starting to get a little worried that we are warming at the high end of what [climate models predicted],” says Gettelman.
“We’ll see,” Dessler agrees. “The next few months will tell us if we’ve really broken the climate.”
Copyright 2024 NPR
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During the mission's loop around the moon, the crew took geological observations of places of interest on the lunar surface with their own eyes and snapping thousands of photos of the surface.
Historic mission: The Artemis II astronauts are making their way back to Earth after the lunar flyby. The crew became the first astronauts in over 50 years to fly around the far side of the moon. They also experienced a solar eclipse. The crew will return to Earth on Friday and splash down off the coast of California. NASA says a landing on the lunar surface won't happen until 2028, at the earliest.
Read on. . . to look at the photos they captured.
The Artemis II astronauts are making their way back to Earth after the lunar flyby.
The crew became the first astronauts in over 50 years to fly around the far side of the moon. They also experienced a solar eclipse.
During the mission's loop around the moon, the crew took geological observations of places of interest on the lunar surface with their own eyes and snapping thousands of photos of the surface.
The crew will return to Earth on Friday and splash down off the coast of California. NASA says a landing on the lunar surface won't happen until 2028, at the earliest.
Here is what they captured.
Copyright 2026 NPR
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Eastside residents are invited to a series of field trips this month to learn how air-quality sensors will be installed across Boyle Heights and East Los Angeles, in an effort to improve air quality and extreme heat in the community.
More details: The nonprofit Climate Resolve, in partnership with Promesa Boyle Heights and California Climate Investments, is hosting two field trips on April 11 and April 18 for residents to witness the installation. Free shuttle transportation will be provided.
Why it matters: Through these field trips, Eastsiders will get to see how and where air quality will be measured in their neighborhoods. Once installed, the monitors will measure wind, black carbon, ozone, particulate matter, and nitrogen dioxide levels.
Read on... learn how to participate.
This story first appeared on The LA Local.
Eastside residents are invited to a series of field trips this month to learn how air-quality sensors will be installed across Boyle Heights and East Los Angeles, in an effort to improve air quality and extreme heat in the community.
The nonprofit Climate Resolve, in partnership with Promesa Boyle Heights and California Climate Investments, is hosting two field trips on April 11 and April 18 for residents to witness the installation. Free shuttle transportation will be provided.
At the April 18 event, the nonprofit City Plants will also give out free potted fruit and shade trees. Proof of L.A. residency is required to receive a tree.
Through these field trips, Eastsiders will get to see how and where air quality will be measured in their neighborhoods. Once installed, the monitors will measure wind, black carbon, ozone, particulate matter, and nitrogen dioxide levels.
Historically, the Eastside has been plagued by high smog and poor air quality due to nearby freeways, rail yards, and industrial activities. East L.A. is crisscrossed by heavily trafficked freeways like the I-5, I-10 and I-710.
Compared to more affluent neighborhoods, areas like Boyle Heights and East L.A. have fewer trees and parks, which naturally help filter pollutants and improve air quality.
As a result, residents in these communities often experience poorer air quality, which contributes to health issues. For example, people in Boyle Heights are 75 to 86% more likely to develop asthma than those in other parts of California, according to a 2023 case study by East LA Community Corporation.
When: 10 a.m. to 1:30 p.m. Saturday, April 11
When: 10 a.m. to 1:30 p.m. Saturday, April 18
Register at bit.ly/CommunityAirQuality
For questions, call or message 213-267-4247
Heads up: The address for each event will be provided the week of that event.
Freelance writer Valeria Macias contributed to this report.
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An expert says fires may destroy coyote dens and disrupt territories, which is why SoCal residents may be seeing more coyotes during mating season now.
Why it matters: While coyotes are mostly afraid of humans, packs can include aggressive coyotes that can be dangerous to humans and pets.
Why now: Spring is mating season, during which coyotes are more active and mark their territories while looking for mates.
What to do if you see one: An expert says it's good to carry a noisemaker like a whistle or a cowbell, and even bear spray. Throwing a rock at a coyote could also discourage it from approaching you.
Go deeper: How to life safely with coyotes.
It’s spring, and that means coyote mating season, not just in Southern California wildlands, but also in the urban landscape. While it’s hard to say whether there are more coyotes roaming the region, the fact that it's mating season means you are more likely to see one.
“Animals are sort of out and about. They're vocalizing. They’re scent marking. They're grooming, they're moving around, they're looking for mates,” said Ted Stankowich, a professor of biological sciences at California State University, Long Beach.
He hasn’t studied the effects of the Palisades and Eaton fires on coyotes, but said fires often destroy coyote dens and disrupt their territories.
“Where one pack might have dominated one sort of larger territory, that territory might be split up. And now you have two packs in there, and you might have two breeding females and more pups,” he said, which can lead to more interactions with humans.
Most coyotes are afraid of people, Stankowich said, but packs may include an aggressive member. Here are his suggestions when encountering coyotes:
What to expect: Mostly sunny skies and cooler temperatures. L.A. and Orange County beaches will see temperatures in the mid 60s to around 70 degrees, though some Orange County coastal areas could reach 76 degrees.
Read on ... to learn about the rain coming later this week.
After a warm weekend, Southern California will see cooler temperatures this week and even some rain over the weekend.
L.A. and Orange County beaches will see temperatures in the mid 60s to around 70 degrees, though some Orange County coastal areas could reach 76 degrees.
Meanwhile, daytime highs for the valleys and Inland Empire will reach into the low 80s, with the warmest areas expected to reach 84 degrees. Coachella Valley will see temperatures in the 90s.
Looking ahead, weekend rain is in the forecast starting Friday through Saturday. We could get anywhere between a quarter to a full inch of rain, with the higher amounts of rainfall more likely for higher elevations. There's also a chance of thunderstorms that could produce heavy downpours. For anyone going to Coachella, it looks like rain is likely for Saturday.
