Greenhouse gas remediation

Greenhouse gas remediation projects are a type of geoengineering and seek to remove greenhouse gases from the atmosphere, and thus tackle the root cause of climate change. These techniques either directly remove greenhouse gases, or alternatively seek to influence natural processes to remove greenhouse gases indirectly. The discipline overlaps with carbon capture and storage and carbon sequestration, and some projects listed may not be considered to be geoengineering by all commentators, instead being described as mitigation.

Carbon sequestration

A wide range of techniques for carbon sequestration exist. These range from ideas to remove CO2 from the air, flue gases and by preventing carbon in biomass from re-entering the atmosphere.

CFC photochemistry

Atmospheric CFC removal is an idea which suggests using lasers to break up CFCs, a powerful greenhouse gas, in the atmosphere.

Methane removal

Methane potentially poses major challenges for remediation. It is around 20 times as powerful a greenhouse gas as CO2.. Large quantities may be outgassed from permafrost and clathrates as a result of global warming, notably in the Arctic.

There are no known geoengineering proposals for the remediation of methane. However, methane is removed by several existing processes, which could be enhanced:

* Combustion - methane in the atmosphere is destroyed as it passes through fires, power stations, vehicle engines, etc.
* Chemical decomposition - reaction with hydroxyl radicals produced from photochemical decomposition of ozone in the stratosphere. This process could be enhanced using ozone addition or lasers. Lasers could also directly degrade methane by photochemical decomposition.
* Biological decomposition - by bacteria in soils

From http://en.wikipedia.org/