A new study published Thursday in Science magazine projects that the Earth's temperature will rise even more than expected in the coming years due to the changing composition of clouds.
The study jointly carried out by two Yale University researchers - Ivy Tan and Trude Storelvmo - and a third at a California laboratory - Mark D. Zelinka - begins with the premise that most models that have tried to predict the temperature increase stemming from human activity have underestimated the significant impact of clouds.
"How much global average temperature eventually will rise depends on the Equilibrium Climate Sensitivity (ECS), which relates atmospheric CO2 concentration to atmospheric temperature," the study said. "For decades, ECS has been estimated to be between 2 degrees Celsius and 4.6 degrees Celsius, with much of that uncertainty owing to the difficulty of establishing the effects of clouds on Earth's energy budget."
But using highly specific NASA data about clouds and their chemical composition, the researchers determined that the ice-water ratio in so-called mixed-phase clouds was incorrect in global models, according to YaleNews, a publication of that prestigious university's Office of Public Affairs & Communication.
In a warmer climate, the ratio of ice in mixed-phase clouds would be less than previously estimated and thus lead to greater climate sensitivity, it said, adding that this is because a higher ratio of ice in clouds in the upper atmosphere results in less warming on the Earth's surface.
Factoring in the projected lower ratio of ice, the researchers found that ECS could be between 5 degrees Celsius and 5.3 degrees Celsius.
Citing the scientists, YaleNews reported that "such an increase could have dramatic implications for climate change worldwide."