Researchers found that reduced low-cloud cover over land slightly mitigates global warming, although temperatures continue to rise. This discovery, based on advanced measurements, emphasizes the importance of accurate climate data to improve models and guide policy decisions.
Researchers at McGill University have found that changes in cloud patterns are having a slight cooling effect on global warming. Although greenhouse gases remain the primary driver of rising temperatures, a decrease in low-cloud cover over land is modestly reducing the amount of heat trapped near the Earth’s surface.
“We started this research to observationally verify the increase of greenhouse effect of the Earth atmosphere,” said Yi Huang, Associate Professor in McGill’s Department of Atmospheric and Oceanic Sciences who conceived a recent study published in Nature, “We indeed verified that, although to our surprise we also found an offsetting effect due to changes in clouds.”
Observational Evidence of Clouds’ Impact
“Without these cloud changes, the surface would warm even faster,” said Lei Liu, a graduate student in McGill’s Department of Atmospheric and Oceanic Sciences and the first author of this study. “This work offers observational truth about how clouds affect warming, which can be used to improve climate models and guide environmental policies,” said Liu.
To discover this surprising effect, the team used the measurements of a key radiative instrument, the Atmospheric Emitted Radiance Interferometer (AERI), along with satellite data, climate models, and a technique called “optimal spectral fingerprinting” co-designed by Yi Huang and Lei Liu to isolate the effects of clouds from other atmospheric processes.
Understanding Longwave Radiation and Cloud Changes
The researchers focused on longwave radiation, the heat energy Earth emits back into the atmosphere. Usually, clouds trap some of this heat and send it back to the ground. But as the climate warms, there are fewer low clouds in some areas, which means less heat is returned to the surface.
McGill’s Atmospheric and Oceanic Department, which operates three AERI instruments in Montreal, looks to continue using their critical data for understanding regional climate dynamics and enhancing climate modeling, the researchers said.
“Our research emphasizes the value of precise, long-term climate observations,” said John Gyakum, co-author and Professor in the Department of Atmospheric and Oceanic Sciences. “This is essential for understanding Earth’s response to global warming and making informed decisions for future generations.”
The researchers cautioned that their discovery does not throw doubt on global warming.
“It’s like having a thermostat that adjusts itself a little,” the researchers explained. “But even with this adjustment, the room is still heating up.”
Reference: “Clouds reduce downwelling longwave radiation over land in a warming climate” by Lei Liu, Yi Huang and John R. Gyakum, 15 January 2025, Nature.
DOI: 10.1038/s41586-024-08323-x
This research was funded by grants of the Natural Sciences and Engineering Research Council of Canada (RGPIN-2019-04511) and the Environment and Climate Change Canada (EDF-CA-2021i022) awarded to Yi Huang as Principal Investigator.
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5 Comments
In thousands of years, the earth’s temperature will change completely. At first, when the Milky Way objects approach the sun, the earth’s temperature will increase, but after a few weeks, the earth will be very cold because thick clouds will block the sunlight. This event has been repeated many times in A few billion years ago, if the small stars of the Milky Way did not join the Sun, a few billion years ago the Earth would have cooled and the evolution of mammals would not have occurred. In all the stars of the Milky Way Galaxy, no system except Earth has advanced life. The Solar System is one of the rarest. There are systems of existence, probably one out of a trillion galaxies may have life, but not intelligent life
All Hail Zorp!
I would love to slap everyone who thinks global warming is real.
Of course global warming is real. Just not the man made one and certainly not the CO2 rubbish. Climate “scientists and politicians like Al Gore” are pushing this to make money or profit from (research grants).
Cloud albedo effects were totally ignored from these so called scientist and play the biggest role how the sun effects earth climate. Without water vapour we would have an ice earth, doesn’t matter the minuscule amount of Co2. Co2 ist actually good gives are more food!
Would be time to set the record straight and have science debates again and not propaganda.
Cyclical natural phenomena, proven by archeology and geology. Right – not man made and not CO2 rubbish.