Scientists look beyond climate change and El Nino for other factors that heat up Earth

Scientists are wondering if global warming and El Niño have an accomplice in fueling this summer's record-shattering heat.
The European agency Copernicus reported that July was one-third of a degree Celsius (six-tenths of a degree Fahrenheit) hotter than the old record. That's a bump in heat that is so recent and so big, especially in the oceans and even more so in the North Atlantic, that scientists are split on whether something else could be at work.

Scientists agree that by far the biggest cause of the recent extreme is climate change from the burning of coal, oil and that has triggered a long upward trend in temperatures. A natural El Niño, a temporary warming of parts of the Pacific that changes weather worldwide, adds a smaller boost. But some researchers say another factor must be present.
"What we are seeing is more than just El Niño on top of climate change," Copernicus Director Carlo Buontempo said.

One surprising source of added warmth could be cleaner air resulting from new shipping rules. Another possible cause is 165 million tons (150 million metric tons) of water spewed into the atmosphere by a volcano. Both ideas are under investigation.

THE CLEANER AIR POSSIBILITY

Florida State University climate scientist Michael Diamond says shipping is "probably the prime suspect."

Maritime shipping has for decades used dirty fuel that gives off particles that reflect sunlight in a process that actually cools the climate and masks some of .

A hiker walks past the Hole-in-the-Rock at Papago Park during sunrise July 17, 2023, in Phoenix. Scientists say by far the biggest cause of the recent extreme warming is human-caused climate change and a natural El Nino. But some say there’s got to be something more. Credit: AP Photo/Ross D. Franklin, File
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Cargo ships are seen lined up outside the Port of Los Angeles, Feb. 23, 2021, in Los Angeles. Scientists say by far the biggest cause of the recent extreme warming is human-caused climate change and a natural El Nino. But some say there’s got to be something more. Credit: AP Photo/Mark J. Terrill, File
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This satellite image made by the Japanese weather satellite Himawari-8 shows the eruption of the Hunga Tonga-Hunga Ha'apai undersea volcano at the Pacific nation of Tonga on Jan. 15, 2022. Scientists say by far the biggest cause of the recent extreme warming is human-caused climate change and a natural El Nino. But some say there’s got to be something more. Credit: Japan Meteorology Agency via AP, File
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Women shelter under a tree as a dust storm moves across the village of Bulla Hagar in northern Kenya, Aug. 19, 2022. Scientists say by far the biggest cause of the recent extreme warming is human-caused climate change and a natural El Nino. But some say there’s got to be something more. Credit: AP Photo/Brian Inganga, File
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