GEOENGINEERING: SPF FOR EARTH

Don't miss the last quote: The G8 leaders apparently did.

If Cutting Carbon Isn't Enough, Can Climate Intervention Turn Down the Heat?
Geoengineering could help stave off global warming, but it could also create some big problems
Nikhil Swaminathan, June 5, 2007 (Scientific American)

WHO
Ken Caldeira, climate scientist, and Damon Matthews, ecologist, Carnegie Institution of Washington's Department of Global Ecology, Gregory Benford, physicist, University of California, Irvine
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WHAT
Caldeira & Matthews authored a Carnegie study discussing mirror-supporting satellites in space to reflect back the sun’s warming rays and light-reflecting particles in the stratosphere to block the sun's rays as methods of coping with global warming.

WHEN
The study was published this week.

WHERE
- The Carnegie Institution of Washington's Department of Global Ecology is based at Stanford University in Palo Alto, CA.
- Published in Proceedings of the National Academy of Sciences USA.

WHY
- The Geoengineering methods could impede warming but it would then be disasterous to remove them.
- Geoengineering: climate altering projects like blocking the sun, reforestation, sequestering CO2 in the ocean or geologic structures.
- Results of a constructed model examining the consequences of emissions continuing at current rates: by 2100 Earth's surface temperature up 3.5 degrees Celsius (6.3 degrees Fahrenheit) from 1900 & some Arctic temps up 6 degrees C (10.8 degrees F).
- Results with geoengineering between 2000 and 2075 to decrease solar radiation reaching earth: temperatures in tropical regions dip slightly (0.35 degree C/0.63 degree F) and climb 1 degree C (1.8 degrees F) in the Arctic.
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- If a geoengineering scheme were halted or failed after initially cooling things off, the earth would warm at 20 times the current rate of 0.2 degree C (0.36 degree F/decade).
- Rain: Models indicate rainfall can be manipulated. Warming oceans lead to more rainfall over the ocean; increased CO2 lowers plant evaporation and decreases rainfall in the tropics. With deflection, the ocean will not warm but tropical rains will be affected, leaving rain ten times less than with unmitigated warming.
- Other authorities question these conclusions and suggest more research is necessary.

QUOTES
- Caldeira: “As far as I know, this is the first century-scale, time-dependent simulation of a geoengineering scheme…The positive result is you can ramp up geoengineering along with the carbon dioxide…Within a decade, you would get most of the cooling effect of a geoengineering scheme, and in two decades you'd get all of it."
- Caldeira: "The risk-averse strategy is to reduce emissions."
- Benford: "The missing stat [here] is to assume that we will make our policies depend solely on climate models…However, you just had 20 years when you could try to do these other measures, such as cutting carbon emissions."