Heat Records Broken Across Earth
On the whole, Earth has warmed roughly 2 degrees Fahrenheit since the 19th century and will continue to grow hotter until humans essentially halt all emissions from fossil fuels and stop deforestation.
But other factors layered on top of human-caused warming may have helped temperatures accelerate dramatically in recent months. For instance, a cyclical phenomenon in the Pacific Ocean known as the El Niño-Southern Oscillation causes year-to-year fluctuations by shifting heat in and out of deeper ocean layers. Global surface temperatures tend to be cooler during La Niña years and hotter during El Niño years.
“A big reason we’re seeing so many records shattered is that we’re transitioning out of an unusually long three-year La Niña, which suppressed temperatures, and into a strong El Niño,” Dr. Hausfather said.
That likely portends more heat. The current El Niño is just getting underway and many researchers don’t expect it to peak until December or January, with global temperatures seeing another surge in the months thereafter. That means that next year could be even hotter than this year, scientists said.
Other dynamics may be at work, too. The North Atlantic has seen record heat since early March, before El Niño conditions began. One factor may be a subtropical high pressure system known as the Azores High that has weakened the winds blowing over the ocean and limited the amount of dust blowing from the Sahara, which normally helps cool the ocean.
Those weather patterns could change in the weeks ahead, said Dr. McNoldy of the University of Miami. “But even then we’d probably be going from insanely record-breaking temperatures down to just extremely record-breaking,” he said.
Other researchers have suggested that recent efforts to clean up sulfur pollution from ships around the world may be pushing up temperatures slightly, since sulfur dioxide tends to reflect sunlight and cool the planet somewhat. That precise impact is still being debated, however.
Source: The New York Times
