Now, new findings reported today in the journal Nature Geoscience make the case that the effects of cloud loss are dramatic enough to explain ancient warming episodes like the PETM — and to precipitate future disaster. Climate physicists at the California Institute of Technology performed a state-of-the-art simulation of stratocumulus clouds, the low-lying, blankety kind that have by far the largest cooling effect on the planet. The simulation revealed a tipping point: a level of warming at which stratocumulus clouds break up altogether. The disappearance occurs when the concentration of CO2 in the simulated atmosphere reaches 1,200 parts per million — a level that fossil fuel burning could push us past in about a century, under “business-as-usual” emissions scenarios. In the simulation, when the tipping point is breached, Earth’s temperature soars 8 degrees Celsius, in addition to the 4 degrees of warming or more caused by the CO2 directly.
Huber said the stratocumulus tipping point helps explain the volatility that’s evident in the paleoclimate record. He thinks it might be one of many unknown instabilities in Earth’s climate.
Natalie WolchoverSchneider and co-authors have cracked open Pandora’s box of potential climate surprises, he said, adding that, as the mechanisms behind vanishing clouds become clear,all of a sudden this enormous sensitivity that is apparent from past climates isn’t something that’s just in the past. It becomes a vision of the future.
A truly apocalyptic scenario that would completely disrupt the climate and ecosystems over the entire surface of Earth. Fortunately it is still decades away by best current estimates – on the other hand measures against global warming are lagging behind targets and the window for action is getting smaller with each passing year. I personally expect we will need efficient solutions for carbon recapture planet-wide to finally get global warming under control.
Clouds come in diverse shapes — sky-filling stratus, popcorn-puff cumulus, wispy cirrus, anvil-shaped nimbus and hybrids thereof — and span many physical scales. Made of microscopic droplets, they measure miles across and, collectively, cover most of the Earth’s surface. By blocking sunlight from reaching the surface, clouds cool the planet by several crucial degrees. And yet, they are insubstantial, woven into greatness by complicated physics. If the planet’s patchy white veil of clouds descended to the ground, it would make a watery sheen no thicker than a hair.
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