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 global warming. 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.^[1]

Carbon sequestration

Main articles: Bio-energy with carbon capture and storage, Carbon sequestration, Carbon dioxide removal, and Carbon dioxide air capture

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, such as with BECCS.

CFC photochemistry

Atmospheric CFC removal is an idea which suggests using lasers to break up CFCs, a powerful greenhouse gas, in the atmosphere.^[2]

Methane removal

Methane potentially poses major challenges for remediation. It is around 20 times as powerful a greenhouse gas as CO₂.^[3] Large quantities may be outgassed from permafrost and clathrates^[4] as a result of global warming, notably in the Arctic.^[5]

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

• 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.
• Biological decomposition — by bacteria in soils^[6]

See also

• Solar radiation management
• Carbon dioxide removal
• Geoengineering

References

1. ^ Wigley TM (October 2006). "A combined mitigation/geoengineering approach to climate stabilization". Science 314 (5798): 452–4. Bibcode 2006Sci...314..452W. doi:10.1126/science.1131728. PMID 16973840. http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=16973840. 
2. ^ Stix, T.H. (7-9 Jun 1993). "Removal of chlorofluorocarbons from the troposphere". 1993 IEEE International Conference on Plasma Science. Vancouver, BC, Canada: IEEE. p. 135. doi:10.1109/PLASMA.1993.593398. ISBN 0-7803-1360-7. http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&arnumber=593398&isnumber=12731. 
3. ^ "Methane as a Greenhouse Gas CCSP Research Highlight 1". U.S. Climate Change Science Program. January 2006. http://www.climatescience.gov/infosheets/highlight1/default.htm. 
4. ^ Buffett, B.; Archer, D.. "Time-dependent response of the marine clathrate reservoir to climatic and anthropogenic forcing". American Geophysical Union. Spring Meeting 2005. Bibcode 2005AGUSM.U33A..05B. 2005AGUSM.U33A..05B. 
5. ^ "Methane Release from Arctic Clathrates Could Threaten Global Climate". International Polar Foundation. 4 June 2008. http://www.sciencepoles.org/index.php?/news/methane_release_from_arctic_clathrates_could_threaten_global_climate/&uid=1231&pg=9. 
6. ^ Reeburgh, William S., and David T. Heggie (1977). "Microbial methane consumption reactions and their effect on methane distributions in freshwater and marine environments". Limnology and Oceanography 22 (1): 1–9. doi:10.4319/lo.1977.22.1.0001. http://www.aslo.org/lo/toc/vol_22/issue_1/0001.pdf.