Climate engineering to reverse global warming may impact biodiversity: Experts

Can the impact of global warming be lessened by deploying sun-shields in space and by injecting sulphates in the upper atmosphere to reduce the amount of solar energy reaching the earth?

Environmental scientists and other experts are currently grappling with the proposed geoengineering technologies and are studying the impact they could have on biodiversity.

Geoengineering is the deliberate intervention in the earth's climate system to moderate global warming.

The experts believe Sunlight Reflection Methods (SRMs) and Carbon Dioxide Removal (CDR) techniques could reduce the magnitude of climate change but are likely to have unintended impacts on biodiversity with significant risks and uncertainties.

The experts' report on geoengineering in relation to biodiversity is being discussed at the ongoing 11th meeting of Conference of Parties (COP11) to the Convention of Biodiversity (CBD) here.

Over 170 countries are attending the meet, discussing various issues related to biodiversity.

The experts believe reducing emissions is the best strategy to avoid climate change. "But that is not happening. With global temperature increases of more than four degrees projected, we need to study viability of other actions," Phil Williamson of the University of East Anglia, who headed the group, told IANS here.

The group, which was constituted by the CBD in 2010 and submitted its report to COP11, called for continued research on geoengineering and its governance.

The group defined geoengineering as a deliberate intervention in the planetary environment of a nature and scale intended to counteract the anthropogenic (human impact) on climate.

The proposed SRM techniques aimed at reflecting a portion of solar radiation back into space include injecting sulphates into the upper atmosphere, increasing cloud concentration, particularly over ocean areas and modifying land or ocean surfaces.

"SRM could reduce the worst effects of future climate change, although there are many uncertainities and problems with that approach," says the report.

SRM techniques however would not address the root cause of human-driven climate change arising from increased greenhouse-gas concentrations in the atmosphere, pointed out Williamson, who is also associated with  the British Natural Environment Research Council.

The experts cautioned that SRM could have an impact on the ozone layer and on the quantity and quality of light, affecting plant production. "There will be consequences for crop yields and biodiversity if plant albedo (reflected sunlight) were reduced and unabated ocean acidification could impact marine biodiversity," says the report.

CDR techniques are aimed at reducing atmospheric Carbon Dioxide. CDR effectiveness is less and its impacts would be highly technique-specific, concluded the experts.

The group said the transboundary impacts of several geoengineering methods would require full international agreement before implementation and that may not be easy to achieve.