IS GEOENGINEERING WORTH THE RISK?

TINKERING WITH THE TROPOSPHERE

To wrap the globe with a reflective blanket dimming the sun’s radiation to cool the environment and so trying to remediate the climate change is one of the last research fads on environmental science. But will this last tampering with Nature be free of cost for humanity?  

FOCUS ON POVERTY: GEOENGINEERING ISN’T WORTH THE RISK (from an article by Roger Williamson,in SciDev.Net [global@team-scidev.net], Jan 20, 2014)

 

 Last month, SciDev.Net reported on a study highlighting the need for international regulation of geoengineering field trials, which said that scientists around the world conduct this research in a legal vacuum.  (For a definition of geoingeneering, see below)

It’s easy to see why geoengineering is attractive to scientists. Finding a technological fix for climate change is a nice, big, juicy project, with lots of scope for lucrative research applications and the chance of a place in the pantheon of scientific greats or even a Nobel Prize. And from the point of view of diplomats too, at a time when climate talks are in trouble, it is tempting to hope for a solution that avoids excessive negotiations.

A study published last week by researchers from the University of Reading, UK, suggests that large geoengineering efforts could have side effects that would disproportionately harm the globe’s poorest people. [1] It argues that a massive injection of sulfate particles into the upper atmosphere may well lower average global temperatures by reflecting sunlight, but this could also cause huge changes to rainfall patterns around the equator — with potentially devastating impacts for poor people.But the implications of such grandiose engineering projects are far from clear. So, as well as considering the statutory regulation of geoengineering research, policymakers should think over the ethics of investing in such strategies — given their uncertainty, would the money be better spent elsewhere?

Full article: http://www.scidev.net/global/engineering/analysis-blog/focus-on-poverty-geoengineering-isn-t-worth-the-risk.html 

Geoengineering by injection of reflective aerosols into the stratosphere has been proposed as a way to counteract the warming effect of greenhouse gases by reducing the intensity of solar radiation reaching the surface. Here, climate model simulations are used to examine the effect of geoengineering on the tropical overturning circulation. The strength of the circulation is related to the atmospheric static stability and has implications for tropical rainfall. The tropical circulation is projected to weaken under anthropogenic global warming. Geoengineering with stratospheric sulfate aerosol does not mitigate this weakening of the circulation. This response is due to a fast adjustment of the troposphere to radiative heating from the aerosol layer. This effect is not captured when geoengineering is modelled as a reduction in total solar irradiance, suggesting caution is required when interpreting model results from solar dimming experiments as analogues for stratospheric aerosol geoengineering. ( Angus J Ferraro, Eleanor J Highwood and Andrew J Charlton-Perez, Published 8 January 2014, http://iopscience.iop.org/1748-9326/9/1/014001/http://iopscience.iop.org/1748-9326/9/1/014001/ )