Geoengineering is perhaps not something that is currently widely known by the public, however it has the potential to be a major player in our future climate.
Broadly defined by the US National Academy of Science (1992) as:
"Large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry"
With Marchetti (1977) first coining the term as a description of CO₂ disposal via injection into sinking thermohaline currents.
So.....?
Put simply, the surface temperature of the Earth results from the net balance of incoming solar (shortwave) radiation and outgoing terrestrial (long wave) radiation (Kiehl and Trenberth, 1997). Geoengineering options attempt to rectify the current and potential future radiative imbalance via either: reducing the amount of solar radiation absorbed by the Earth. This is called Solar Radiation Management (SRM).
The other option is to physically remove CO₂ from the atmosphere and preventing it from returning there. Which can be subdivided into the enhancement or creation of (a) Land and (b) Ocean carbon sinks or (c) creating new sinks. This is known as Carbon Dioxide Removal (CDR).
Why now?
Geoengineering has been proposed in order to moderate anthropogenic climate change and despite some serious social and policy maker opposition, proposals are undergoing serious consideration.
There has been a recent realisation that existing mitigation efforts are proving to be hugely ineffectual on a global scale, shown by post-2000 anthropogenic CO₂ trends as seen in Canadell et al (2007). this has lit a beacon of interest in Geoengineering (Crtuzen, 2006), with a growing number of proposals being brought to light in scientific literature (Boyd, 2008). Both Vaughan and Lenton (2009) and Lenton and Vaughan (2011) have given a broad review of geoengineering proposals.
I've tried to give a broad overview of Geoengineering here, however there are many major caveats and problems associated with it. I'll go into these in later posts.
Until then...
Thanks for the interesting post. I suppose that in my wildesr dreams I do envisage mass extraction of CO2 from the atmosphere being buried beneath the ocean floor - an anthropgenic speeding up the carbon cycle. Ultimately I believe some solution like this will be implemented on a large scale.
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