Global warming tactic cools climate but won’t help corals, say researchers

Global warming tactic cools climate but won’t help corals, say researchers









(PhysOrg.com) --
“Geoengineering” experiments proposed to reduce global warming by
blocking sunlight with atmosphere-injected particles may cool the world
but still leave carbon dioxide levels dangerously high, Stanford
scientists say.
Sunlight-blocking particles would fail to solve the problems of ocean
acidification and dying corals, two significant repercussions of
climate change, according to a study by Ken Caldeira of Stanford
University and the Carnegie Institution, Damon Matthews of Concordia
University, and Long Cao of the Carnegie Institution. Atmospheric carbon dioxide
dissolves in ocean water, making it more acidic and difficult for
animals to build their shells or skeletons, especially corals.

Proponents of geoengineering have called for injecting small,
reflective particles into the atmosphere to partially block sunlight and
cool the earth, just as ash from an erupting volcano
does. The resulting carbon-dioxide-rich climate would cause land
plants to grow more vigorously, hold onto more carbon and release less
to the ocean. But the difference would not be enough to fundamentally
alter the plight of coral reefs, Caldeira said.

The researchers used computer models of the Earth’s climate system and
biosphere to simulate the effect of sunlight-reflecting particles on
climate and ocean chemistry.
Such geoengineering methods “might be able to address some of the
climate effects of carbon dioxide but they don’t fundamentally address
the chemical effects posed by carbon dioxide,” Caldeira said.

“Instead of taking till 2050 until there’s no place left in the ocean
where corals can survive, it might be 2053. The carbon cycle effects of
the geoengineering might delay that outcome in the ocean by a few years
but wouldn’t prevent those outcomes from occurring,” he said. The
scientists’ work was published in Geophysical Research Letters.

Despite the limitations, Caldeira and many other scientists support
geoengineering research. David Victor, director of the Program on Energy
and Sustainable Development at Stanford, presents a case for studying
and testing such tactics as emergency measures.

“Geoengineering could provide a useful defense for the planet—an
emergency shield that could be deployed if surprisingly nasty climatic
shifts put vital ecosystems and billions of people at risk,” Victor
wrote in Foreign Affairs with colleagues from Carnegie Mellon University
and the University of Maryland.

The paper, entitled The Geoengineering Option, presents methods for
increasing the earth’s reflectivity, such as injecting particles in the
atmosphere, as “the most promising method for rapidly cooling the
planet.” The authors contend that injecting reflective materials into
the atmosphere would be easy and cost-effective and could crudely offset
warming.

Although these methods potentially interfere with weather patterns and fail to reduce carbon dioxide concentrations and ocean acidification,
Victor and colleagues call for a broad and solid foundation of
geoengineering research. “The scientific academies in the leading
industrialized and emerging countries—which often control the purse
strings for major research grants—must orchestrate a serious and
transparent international research effort funded by their governments,”
Victor and his colleagues wrote in the paper.


Source:-
http://phys.org/news165847604.html


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