‘We’re changing the clouds.’ An unintended test of geoengineering is fueling record ocean warmth

The Atlantic Ocean is running a fever . Waters off Florida have become a hot tub, bleaching the third-largest barrier reef in the world. Off the coast of Ireland, extreme heat was implicated in the mass death of seabirds. For years, the north Atlantic was warming more slowly than other parts of the world. But now it has caught up, and then some. Last month, the sea surface there surged to a record 25°C—nearly 1°C warmer than the previous high, set in 2020—and temperatures haven’t even peaked yet. “This year it’s been crazy,” says Tianle Yuan, an atmospheric physicist at NASA’s Goddard Space Flight Center. The obvious and primary driver of this trend is society’s emissions of greenhouse gases, which trap heat that the oceans steadily absorb. Another influence has been recent weather, especially stalled high-pressure systems that suppress cloud formation and allow the oceans to bake in the Sun. But researchers are now waking up to another factor, one that could be filed under the category of unintended consequences: disappearing clouds known as ship tracks. Regulations imposed in 2020 by the United Nations’s International Maritime Organization (IMO) have cut ships’ sulfur pollution by more than 80% and improved air quality worldwide. The reduction has also lessened the effect of sulfate particles in seeding and brightening the distinctive low-lying, reflective clouds that follow in the wake of ships and help cool the planet. The 2020 ...
Source: ScienceNOW - Category: Science Source Type: news