February 19, 2014
Ending Geoengineering Prematurely May Worsen Global Warming
Ranjini Raghunath for redOrbit.com - Your Universe Online
A proposed mitigation technique which involves spewing sulfur particles into the atmosphere could help combat climate change – but if stopped after being implemented, it could worsen the problem, according to a new study from University of Washington researchers.
Spewing sulfur particles into the air could cool the planet by reflecting sunlight back into space – a technique called solar radiation management (SRM). Scientists believe that it could help bring down global warming, and can be implemented easily and economically.
A Seattle-based private company called Intellectual Venture Laboratories, in fact, proposed building a Stratoshield – a system based on the idea of SRM. They suggested that the StratoShield, when installed, would spew several million metric tons of sulfur dioxide into the stratosphere, and potentially reduce the sun’s radiation globally by 1.8 percent.
But the SRM method would only work if implemented uninterrupted – a possibility that can be achieved only by stringent protocols governing its indefinite use, the researchers believe.
In the new study, published online in Environmental Research Letters, the University of Washington researchers highlight the abrupt and devastating temperature changes that would occur if the technique is stopped after being implemented.
Assuming that global temperatures continue to rise at the current rate, the researchers tried to predict what would happen in the three decades following a 25-year implementation of SRM after the year 2035. Global temperatures would rise by 4°C (7.2F) – twice as much as the temperature rise under conditions without SRM, and potentially the highest increase on record, they found.
“The absolute temperature ends up being roughly the same as what it would have been, but the rate of change is so drastic that ecosystems and organisms would have very little time to adapt to the changes,” stated lead author and graduate student Kelly McCusker, in a press release.
Temperature changes would be greatest in winter near the Polar Regions and in summer in the tropics, when changes are unusual.
“Tropical regions like South Asia and Sub-Saharan Africa are hit particularly hard, the very same regions that are home to many of the world's most food insecure populations,” McCusker stated.
When SRM is implemented, how long it was implemented could also determine the rate of temperature change, in addition to greenhouse gas levels, the researchers believe.
“If we must geoengineer, it does not give us an excuse to keep emitting greenhouse gases,” McCusker added. “On the contrary, our results demonstrate that if geoengineering is ever deployed, it’s imperative that greenhouse gases be reduced at the same time to reduce the risk of rapid warming.”