Radical plan to artificially cool Earth’s climate could be safe, study finds

This
story
was originally published by the Guardian and is reproduced
here as part of the Climate
Desk
collaboration.

A new study contradicts fears that using solar
geoengineering
 to fight climate change could dangerously alter
rainfall and storm patterns in some parts of the world.

Published in the peer-reviewed journal Nature Climate Change,
the analysis
finds that cooling the Earth enough to eliminate roughly half of
warming, rather than all of it, generally would not make tropical
cyclones more intense or worsen water availability, extreme
temperatures, or extreme rain. Only a small fraction of places, 0.4
percent, might see climate change impacts worsened, the study
says.

Many climate experts have warned that cooling the Earth but
keeping twice as much carbon dioxide in the atmosphere as before
industrialization could put some regions at risk.

One scientist who read the paper published on Monday said it was
not comprehensive enough to conclude that solar geoengineering —
most likely involving spraying sulphur dioxide into the atmosphere,
thereby mimicking gas from volcanoes and reflecting the sun’s
heat — would be safe.

Some climate advocacy groups argue that banking on an unproven
technology could hamstring efforts to reduce carbon dioxide still
spewing from power plants and cars.

But study coauthor David Keith, a
Harvard professor who works in engineering and public policy, said
researchers should not rule out geoengineering yet.

“I am not saying we know it works and we should do it now,”
he said. “Indeed, I would absolutely oppose deployment now.
There’s still only a little group of people looking at this,
there’s lots of uncertainty.”

Keith said the study’s main message was that “there is the
possibility that solar geoengineering could really substantially
reduce climate risks for the most vulnerable.”

The findings come as Nairobi hosts a United Nations Environment
Program meeting on limiting climate change. A U.N. report last year
said geoengineering by injecting sulphur dioxide into the
atmosphere may be necessary but would come with
major uncertainties
.

Keith hopes to dispel what he believes may be unsupported
worries. Another scientist, however, said he was overstating the
study’s findings.

The analysis used climate modeling to project what could happen
if the heat of the sun was turned down. Alan Robock, a
geophysics professor and researcher at Rutgers University in New
Jersey, said it did not examine the potential effects of doing that
with the most likely method: spraying aerosols into the
atmosphere.

“They focus in this paper on temperature and water
availability in different regions,” Robock said. “Those are
only two things that would change with stratospheric aerosols.”
He added that previous studies have made similar conclusions.

Robock said one of his studies contains a list of 27 reasons why
Earth-cooling aerosols might be a bad idea. And he added that the
technology could cost hundreds of billions of dollars a year and
would pose complicated ethical questions, such as whether people
have a right to see a blue sky.

“We’re not able right now to say whether, if global warming
continues, we should ever decide to start spraying this stuff into
the stratosphere,” Robock said. “Would solar-radiation
management, would geoengineering make it more dangerous or less
dangerous?

“That’s the question we have to answer, and we don’t have
enough information.”

This story was originally published by Grist with the headline
Radical plan to artificially cool Earth’s climate could be safe,
study finds
on Mar 14, 2019.

Source: FS – All – Ecology – News 2
Radical plan to artificially cool Earth’s climate could be safe, study finds