Scientists explain why the record heat of 2023 has them on edge. Warming may be getting worse

The latest calculations from several scientific agencies showing that Earth obliterated global heat records last year may seem frightening. But scientists worry that what’s behind those numbers could be even worse.

The Associated Press asked more than three dozen scientists in interviews and emails what the shredded records mean. Most said they fear the acceleration of climate change, which is already just shy of the 1.5 degrees Celsius (2.7 Fahrenheit) rise since pre-industrial times that nations had hoped to stay within.

“The heat of the last calendar year was a dramatic message from Mother Nature,” said Katharine Jacobs, a climate scientist at the University of Arizona. Scientists say warming air and water is making costly and deadly heat waves, floods, droughts, storms and wildfires more intense and more likely.

This last year was fantastic.

Average global temperatures surpassed the previous record by just over a quarter of a degree (0.15 degrees Celsius), a large margin, according to calculations Friday by two major U.S. science agencies, the British weather service and a private group founded by a climate organization. skeptical.

Several of the scientists who did the calculations said the climate behaved in strange ways in 2023. They wonder if man-made climate change and a natural El Niño phenomenon were augmented by a strange phenomenon or if “there is something else going on.” system underway,” as NASA said. expressed it by scientist Gavin Schmidt, including a much-discussed acceleration of warming.

A partial answer may not come until late spring or early summer. That’s when a strong El Niño (the cyclical warming of Pacific Ocean waters that affects global weather patterns) is expected to fade. If ocean temperatures, including deep water, continue to set records well into the summer, as in 2023, it would be an ominous hint, they say.

Nearly all scientists who responded to AP’s questions blamed greenhouse gases from burning fossil fuels as the overwhelmingly most important reason the world reached temperatures human civilization had probably not seen before. El Niño, which borders on “very strong,” is the second most important factor, followed by other conditions far behind, they said.

The problem with 2023, said NASA’s Schmidt, is that “it was a very strange year… The deeper you go into it, the less clear it seems.”

Part of that is the timing of the big heat explosion of 2023, according to Schmidt and Samantha Burgess, deputy director of Europe’s Copernicus Climate Service, which earlier this week estimated the warming at 1.48 degrees Celsius above pre-industrial times.

Temperatures are typically higher than normal in late winter and spring, they said. But the highest heat of 2023 began around June and remained at record levels for months.

Deep ocean heat, a major factor in global temperatures, behaved similarly, Burgess said.

Former NASA climate scientist James Hansen, often considered the godfather of global warming science, theorized last year that warming was accelerating. While many of the scientists contacted by the AP said they suspected this was happening, others insisted that the evidence so far only supports a long-predicted, steady rise.

“There is some evidence that the rate of warming over the last decade is slightly faster than the previous decade, which meets the mathematical definition of acceleration,” said UCLA climate scientist Daniel Swain. “However, this is also largely consistent with predictions” that warming would accelerate at some point, especially as airborne particle pollution declines.

The U.S. National Oceanic and Atmospheric Administration estimated that Earth in 2023 had an average temperature of 59.12 degrees (15.08 degrees Celsius). That’s 0.27 degrees (0.15 degrees Celsius) warmer than the previous record set in 2016 and 2.43 degrees (1.35 degrees Celsius) warmer than pre-industrial temperatures.

“It’s almost like we’re moving off the ladder (of normal global warming temperature increases) into a slightly warmer regime,” said Russ Vose, head of global monitoring at NOAA’s National Centers for Environmental Information. He said he sees an acceleration of warming.

NASA and the UK Met Office estimated warming since the mid-19th century to be slightly higher, at 2.5 degrees (1.39 degrees Celsius) and 2.63 degrees (1.46 degrees Celsius), respectively. . Records date back to 1850.

The World Meteorological Organization, combining measurements announced Friday with Japanese and European calculations released earlier this month, pegged 2023 at 1.45 degrees Celsius (2.61 degrees Fahrenheit) warmer than preindustrial temperatures.

Many climate scientists saw little hope of halting warming in the 1.5 degrees target called for in the 2015 Paris agreement that sought to avoid the worst consequences of climate change.

“I do not consider it realistic that we can limit warming (averaged over several years) to 1.5°C,” Woodwell Climate Research Center scientist Jennifer Francis wrote in an email. “It is technically possible but politically impossible.”

“The slowness of climate action and the continued misinformation that catalyzes it has never been due to a lack of science or even a lack of solutions: it has always been, and continues to be, a lack of political will,” said Katharine Hayhoe, chief scientist at The Nature Conservation.

Both NASA and NOAA said the last 10 years, from 2014 to 2023, have been the 10 warmest years they have measured. It is the third time in the last eight years that a global heat record has been set. Randall Cerveny, a scientist at Arizona State University who helps coordinate record-keeping for the WMO, said the big concern is not that a record was broken last year, but that they continue to be broken so frequently.

“The most alarming thing to me is the rapidity of the ongoing change,” Cerveny said.

Natalie Mahowald, a climate scientist at Cornell University, said: “This is just a taste of what we can expect in the future, especially if we continue to fail to reduce carbon dioxide fast enough.”

That’s why so many scientists contacted by The Associated Press are anxious.

“I’ve been worried since the early 1990s,” said Kim Cobb, a climate scientist at Brown University. “I am more worried than ever. “My concern grows with each passing year that global emissions are heading in the wrong direction.”


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