Rapid Loss of Cloud Cover Is Contributing to Record Global Temperatures: Study

Earth’s cloud cover has been shrinking rapidly, contributing to the world’s rising temperatures, according to a new NASA-led analysis of satellite observations.

The researchers found that during each decade of the past 24 years, 1.5 to three percent of the planet’s “storm cloud zones” in the middle latitudes and tropics have been contracting.

“This cloud contraction, along with cloud cover decreases at low latitudes, allows more solar radiation to reach the Earth’s surface. When the contribution of all cloud changes is calculated, the storm cloud contraction is found to be the main contributor to the observed increase of the Earth’s solar absorption during the 21st century,” the authors of the study wrote.

The trend has been associated with changing wind patterns, storm systems shifting poleward and the widening of the tropics — all well-established planetary responses to climate change, a press release from Monash University said.

Fewer clouds mean less sunlight is being reflected back into space, amplifying the warming effect of human-produced greenhouse gas emissions and driving up temperatures worldwide.

Climate scientist Christian Jakob, co-author of the study and a professor of climate modeling at Monash’s School of Earth, Atmosphere and Environment, said reduced cloud cover is now considered the biggest contributor to the increase in the planet’s absorption of solar radiation.

“We’ve long known that changes in atmospheric circulation are affecting clouds,” Jakob said in the press release. “For the first time, we now have research showing those shifts are already driving major changes in how much energy the Earth absorbs. It’s an important piece in the puzzle of understanding the extraordinary recent warming we observed, and a wake-up call for urgent climate action.”

Being able to predict where clouds form more accurately, as well as how much solar radiation they reflect, will be crucial to anticipating the scale and speed of future warming.

Jakob emphasized the importance of leading climate research receiving adequate international support.

“If you want to understand the climate crisis, and prepare for its impacts, you need this kind of data and this kind of analysis,” Jakob said. “It is important for all of us to realize that our climate does not care what people wish it to be, it only responds to our actions. Eliminating science that informs those actions is a perilous strategy.”

Jakob said climate resilience going forward will require a shift in perspective from “climate change” to “weather change.”

“Our mission is to understand how Australia and the world’s weather is being reshaped by a warming climate,” Jakob added. “It’s not just long-term averages that matter, but how the day-to-day and season-to-season conditions we all rely on are changing. Our goal is to provide the knowledge and tools needed to help governments, businesses and communities prepare for what lies ahead.”

The study, “Contraction of the World’s Storm-Cloud Zones the Primary Contributor to the 21st Century Increase in the Earth’s Sunlight Absorption,” was published in the journal Geophysical Research Letters.