By Paul Voosen , Science.  Excerpt: It seems an easy climate solution, almost too good to be true. Greenhouse gas emissions from airplanes are stubbornly difficult to reduce—batteries cannot power a jumbo jet. But in the past few years, scientists and industry have seized on a way to trim airplanes’ climate footprint by limiting the clouds they leave behind. Jet contrails, when they turn into long-lived clouds, trap significant amounts of heat that would otherwise escape Earth—three times more than the carbon dioxide (CO 2 ) emitted by the engines, some studies have suggested. In theory, tweaking flight routes to avoid creating these clouds could slash aviation’s toll on the climate....  Full article at https://www.science.org/content/article/airplane-contrails-may-not-be-climate-villain-once-feared .

By Kasha Patel , The Washington Post.  Excerpt: Penguin poop — sorry, penguin guano — is creating clouds in Antarctica that could be affecting local temperatures, according to  new research published  Thursday in Communications Earth & Environment....  Full article at https://www.washingtonpost.com/climate-solutions/2025/05/22/penguin-guano-clouds-study-climate/ . 

By Nathaniel Scharping , Eos/AGU. Excerpt: In a string of ever-hotter years, 2023 stood out: It was the  warmest on record  (though  2024 will likely surpass it ), with temperatures 1.4°C (2.5°F) above the preindustrial average and 0.17°C (0.3°F) above the previous record set in 2016. One cause for the spike may have been that Earth was just a little darker than it’s been in recent history.  Earth’s albedo , a measure of how reflective the surface is, hit a record low in 2023, according to the authors of a  study in  Science . That record was due mainly to a dearth of bright, low-level clouds, which reflect more solar radiation than land or ocean. The answers to why these clouds were absent and, crucially, whether the trend will continue are still unclear....  Full article at https://eos.org/articles/darker-less-cloudy-earth-contributed-to-record-heat .

By Paul Voosen , Science.  Excerpt: For more than 20 years, NASA instruments in space have tracked a growing imbalance in Earth’s solar energy budget, with more energy entering than leaving the planet. Much of that imbalance can be pinned on humanity’s greenhouse gases emissions, which trap heat in the atmosphere. But explaining the rest has been a challenge. ...George Tselioudis, a climate scientist at NASA’s Goddard Institute for Space Studies ...and his colleagues now think they can explain the growing gap with evidence collected by a remarkably long-lived [Terra] satellite. They find that the world’s reflective cloud cover has shrunk in the past 2 decades by a small but tangible degree, allowing more light in and boosting global warming. ...Tselioudis ... presented the work  last week at a meeting of the American Geophysical Union. Climate scientists now need to figure out what’s causing these cloud changes ...whether the trend is a feedback of climate change that mig...

https://www.science.org/content/article/changing-clouds-unforeseen-test-geoengineering-fueling-record-ocean-warmth By Paul Voosen, Science.  Excerpt: ...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 IMO rule “is a big natural experiment,” says Duncan Watson-Parris, an atmospheric physicist at the Scripps Institution of Oceanography. “We’re changing the clouds.” By dramatically reducing the number of ship tracks, the planet has warmed up faster, several new studies have found. That trend is magnified in the Atlantic, where maritime traffic is particularly dense. In the shipping corridors, the increased light represents a 50% boost to the warming effec...

https://www.sciencemag.org/news/2019/06/aviation-s-dirty-secret-airplane-contrails-are-surprisingly-potent-cause-global-warming Source:   By Katie Camero, Science Magazine. Excerpt: The aviation industry has long been criticized for its large environmental footprint, particularly its climate-warming carbon emissions. But a new study suggests that another byproduct of airplanes—the white contrails they paint across the sky—has an even bigger warming effect, one that is set to triple by 2050. ...A 2011 study suggests that the net effect of these contrail clouds contributes more to atmospheric warming than all the carbon dioxide (CO2) produced by planes since the dawn of aviation. And those effects are predicted to get worse as air traffic—and the resulting cloud coverage—increases: Some estimates suggest global air traffic will quadruple by the year 2050....

https://eos.org/research-spotlights/improving-estimates-of-long-term-climate-sensitivity Source:   By Terri Cook, Eos/AGU. Excerpt: New modeling casts doubt on the suitability of running experiments with fixed sea surface temperatures to understand the effects of cloud aggregation on Earth’s climate. One of the fundamental metrics in climate change research is equilibrium climate sensitivity: the amount that Earth’s long-term, near-surface temperatures will change in response to a doubling of atmospheric carbon dioxide concentrations. Previous research has shown that two spatially dependent processes—the variability of sea surface temperatures and the organization of initially scattered convection (known as convective aggregation)—largely control climate sensitivity by regulating feedbacks related to clouds and water vapor that can amplify or moderate Earth’s ability to radiate heat into space. ...aggregation could actually depend upon sea surface temperature patterns....