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A person hides under a face cover in Manhattan's Central Park during a heat wave in New York on Friday, July 28.
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A construction worker drinks cold water during a heat wave where temperatures have reached over 110 degrees Fahrenheit for 27 consecutive days in Scottsdale, Arizona, on July 28.
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People keep cool in a fountain at New York's Battery Park on Thursday, July 27.
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Yemichael Abebe uses an umbrella to take shelter from the sun while waiting for a bus in Takoma Park, Maryland, on July 27.
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City workers take a break in the shade of a nearby storefront as they lay down new pavement in Woodland Hills, California, on July 27.
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A woman shades herself from the sun along the Brooklyn Bridge in New York on July 27.
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Vendors sell cold drinks near the Lincoln Memorial in Washington, DC, on July 27.
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Snickers, a great horned owl, is sprayed down with water by a volunteer at Liberty Wildlife, an animal rehabilitation center and hospital in Phoenix, on Wednesday, July 26.
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Representatives of the Miami-Dade County Homeless Trust distribute shelter information and bottles of water to people in Miami on July 25.
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Rick White drinks water while cooling down in his tent in "The Zone," Phoenix's largest homeless encampment, on Tuesday, July 25.
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A cactus in Phoenix is affected by the extreme heat and drought. Record-high temperatures in Arizona, combined with a lack of seasonal monsoons, have caused saguaro cactuses at the Desert Botanical Garden to become "highly stressed," according to Chief Science Officer Kimberlie McCue.
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Israel Sanchez, left, and Alfonso Garcia carry a person onto a stretcher in Eagle Pass, Texas, on July 18. The person, who was suffering from dehydration, fell sick after he and his mother were found with a group of migrants who recently crossed the Rio Grande into the United States.
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Roberto Guerrero, left, and his son Jose work in the early morning to install a new air conditioner at a home in Phoenix on July 18. Guerrero is part of perhaps the most essential workforce in town: AC repair techs. "If they need us, we go," he said of the long work hours.
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A person covers their head while trying to stay cool in "The Zone," a vast homeless encampment where hundreds of people reside in Phoenix, on July 18.
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Workers harvest onions overnight in Salem, New Mexico, to avoid working in the heat of the day on July 18.
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A man in Las Vegas puts his head in misters to cool off on July 17.
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A heat advisory sign is shown along Highway 190 at Death Valley National Park in Death Valley, California, on July 16.
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People sit in a crowded room at Phoenix's Justa Center, one of the area's many cooling centers, on July 16.
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A sign warning of extreme heat invites people to "Chill with Jesus" inside a church in Tucson, Arizona, on July 15.
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A firefighter watches flames from the Rabbit Fire approach Gilman Springs Road in Moreno Valley, California, on July 14.
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A person seeking shelter from the heat watches the weather forecast at the First Congregational United Church of Christ in Phoenix on July 14.
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Capt. Darren Noak, a medic with Austin-Travis County Emergency Medical Services, applies a chemical ice pack to a man in Austin, Texas, on July 12.
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A person fishes in Isle of Palms, South Carolina, on July 12.
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A sleeping child is protected from the sun in Los Angeles on July 12.
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A sign displays the temperature on July 12 as jets taxi at Phoenix's Sky Harbor International Airport.
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Kristin Peterson cools off with a cold bandana at the Sunrise Homeless Navigation Center in Austin on July 11.
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The "World's Tallest Thermometer" shows temperatures reaching triple digits in Baker, California, on July 11.
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Steven Rodriguez picks okra in Coachella, California, on July 11.
CNN  — 

As millions bake under a relentless heat wave in the South and Southwest US – and as temperatures soar around the Northern Hemisphere – NASA scientists warned Thursday that we haven’t even seen the worst of El Niño and next year will likely be even warmer for the planet.

Climate change, caused by burning fossil fuels, is unequivocally warming the Earth’s temperature, NASA scientists said.

And El Niño, the natural climate pattern in the tropical Pacific that brings warmer-than-average sea-surface temperatures and influences weather, has only just started in recent months and therefore is not having a huge impact yet on the extreme heat people around the globe are experiencing this summer, said Gavin Schmidt, a climatologist and director of the NASA Goddard Institute for Space Studies.

“It’s really only just emerged, and so what we’re seeing is not really due to that El Niño,” Schmidt told reporters. “What we’re seeing is the overall warmth pretty much everywhere – particularly in the oceans. … The reason why we think that’s going to continue is because we continue to put greenhouse gases into the atmosphere. Until we stop doing that, temperatures will keep on rising.”

Last month was the hottest June on record for the planet, the EU’s Copernicus Climate Change Service reported earlier this month. Several days in July were the planet’s warmest in modern records kept by two climate agencies in the US and Europe.

All of that heat is adding up, and Schmidt said he believes there is a 50-50 chance that 2023 will be the warmest year on record.

But, he added, it is likely that a sweltering 2024 will exceed it, precisely because of El Niño’s influence.

“We anticipate that 2024 is going to be an even warmer year because we’re going to be starting off with that El Niño event,” Schmidt said. “That will peak towards the end of this year, and how big that is is going to have a big impact on the following year’s statistics.”

Scientists also discussed the devastating impact climate change is having on the Earth’s oceans, as North Atlantic Ocean temperatures have soared this summer.

“The oceans are running a fever,” said Carlos Del Castillo, chief of NASA’s Ocean Ecology Laboratory. “This issue with ocean temperature is not a problem that stays in the ocean – it affects everything else.” Castillo noted hotter ocean temperatures can make hurricanes stronger and make ocean levels rice due to glacial melt.

Schmidt noted that rising temperatures are in line with what scientists have predicted as humans burn more fossil fuels and pump more greenhouse gas emissions into the atmosphere.

“Even the things that are unprecedented are not surprising,” Schmidt said.