https://www.science.org/content/article/clearer-skies-may-be-accelerating-global-warming
Excerpt: A new study, published Wednesday in Communications Earth & Environment, suggests one reason for such an acceleration: Earth’s skies are getting clearer and letting in more sunshine.
The study was prompted by a set of NASA instruments in space that since 2001 have tracked the delicate balance of energy entering and leaving the planet. Over the past decade, the instruments, called the Clouds and the Earth’s Radiant Energy System (CERES), have detected a marked rise in the amount of solar energy the planet has absorbed—well beyond the warming expected from rising greenhouse gases. The readings show the planet has become less reflective, as if it recently put on a darker shirt. One reason is a drop in light-reflecting pollution because of power-plant scrubbers and cleaner fuels, the researchers say. They calculate that cleaner air could account for 40% of the increased energy warming the planet between 2001 and 2019.
Climate scientists have long known that pollution declines can lead to warming: Not only do the pollution particles, or aerosols, reflect light into space, but they can also increase the number of droplets in clouds, causing them to grow brighter or last longer. Two years ago, the decline of aerosols became detectable on a global scale. But the climate models used in the new study attributed a startling amount of warming to the pollution drop, says Øivind Hodnebrog, a modeler at Norway’s Center for International Climate Research, who led the work. “That was an eye opener for me, that it was such a big effect.”
