Clouds Aren’t Helping Stop Global Warming as Much as We Thought, Study Says

The reflective power of clouds may be less effective at counteracting global warming than previously thought, according to new research.

Scientists behind the new research looked at clouds that contain both liquid and ice water, known as mixed-phase clouds. Most climate models suggest that clouds will better be able to reflect light into space as global warming speeds up the melting of ice water into a liquid in coming decades. Liquid water tends to reflect more light back into space than ice.

But the new research, published in the journal Science, suggests that most models overestimate how much ice currently exists in mixed-phase clouds. That finding could dramatically increase the forecast speed of temperature rise in the coming decades, with temperatures more than 1°C higher than anticipated in current models, according to the study.

The finding suggests that it will be harder for countries from around the world to keep temperatures from rising less than 2°C (3.6°F) above preindustrial levels by 2100. That’s the goal that countries agreed to at a U.N. conference in Paris in December.

“The evidence is piling up against an overall stabilizing cloud feedback,” study co-author Mark Zelinka, of the Lawrence Livermore National Laboratory, said in a statement. “Clouds do not seem to want to do us any favors when it comes to limiting global warming.”

The study joins growing evidence in recent months suggesting that climate change may be more difficult to halt than scientists previously understood. Research published last month suggested that global sea levels could rise more than 3 feet due to Antarctic ice melt, much more than previously understood, and another study released this week in the journal Science Advances suggests that man-made global warming may be so strong that it affects the way the earth sits on its axis.