https://truthout.org/articles/if-emissions-arent-curbed-clouds-may-disappear/
[links in online article]
If Emissions Aren’t Curbed, Clouds May Disappear
By Dahr Jamail, Truthout
Published February 26, 2019
A study just published in the journal Nature Geoscience shows that if we
continue with business-as-usual fossil fuel emissions, the atmosphere
will hold 1,200 parts per million CO2 in about a century from now, which
will cause stratocumulus clouds to disappear. Their absence could leave
the Earth to warm by a staggering 8 degrees Celsius (8°C).
The computer simulation used in the study showed that once that 1,200
parts per million (ppm) tipping point of atmospheric CO2 is breached,
the Earth’s temperature would soar by 4°C just from the CO2. Then, it
would increase by another 4°C due to the absent clouds no longer
reflecting solar radiation back into space.
Stratocumulus clouds cover around two-thirds of the planet, and play a
key role in keeping the planet cool, due to their white color and
reflective qualities. Research has shown that planetary warming
correlates with the loss of clouds. This is yet another unforeseen
climate feedback loop that could catapult us into catastrophic warming.
Kerry Emanuel, a climate scientist at the Massachusetts Institute of
Technology who is a leading authority on atmospheric physics, told
Quanta Magazine that the results of the study still needed to be
replicated independently, but that the possibility of the simulation
being accurate was “very plausible.”
Crocodiles in the Arctic
It is highly unlikely that most complex life could survive on a planet
that has warmed to 8°C. A previous cataclysmic hot spell gives us clues
as to what Earth’s future could look like.
The Paleocene-Eocene Thermal Maximum (PETM), which occurred 56 million
years ago, was triggered by heat-trapping carbon causing the planet to
gain 6°C. (At the time, the Earth was already several degrees Celsius
warmer than it is now.)
Global mass extinctions resulted, as the oceans warmed dramatically.
Horses, monkeys, and other animals migrated northward as they chased
vegetation that moved into the higher latitudes. Mammal life
miniaturized over many generations as their food became less nutritious
due to the warmer carbon-filled air, and flash flooding and increasingly
violent storms became the norm.
During the PETM, the equatorial regions of Earth were scorched and
nearly completely lifeless, while crocodiles swam in the Arctic.
“Schneider and co-authors have cracked open Pandora’s box of potential
climate surprises,” Matt Huber, a paleoclimate modeler at Purdue
University told Quanta Magazine of the study.
Huber added that, “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.” The tipping point of the loss of
clouds, and the instability it causes, is significant: It helps to
explain the volatility in Earth’s paleoclimate records.
“Climate transitions that arise from this instability may have
contributed importantly to hothouse climates and abrupt climate changes
in the geological past,” reads the abstract of the study. “Such
transitions to a much warmer climate may also occur in the future if CO2
levels continue to rise.”
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