Geoengineering is the way to go

Cautious attitude will result in missing two advantages of many GE methods - speed and power

I was delighted to see an article on geoengineering (GE) in PE (Dec. 2010). But, as I read on my delight turned to dismay. All 3 of the experts quoted seem to see GE as something to be used in the distant future and two of them are reluctant to use it at all. Professor Shepherd calls for 10 years research, perhaps leading to implementation in 15 years. Tim Fox sees artificial trees waiting until wind power is ubiquitous (for the good reason that the process requires a significant energy input which, in the near term, will come from mainly fossil fuel). Professor Launder argues for some form of SRM but sadly he sees it being used only "in a climate emergency" not as a means of avoiding the emergency. 

All this suggests that there will be little help from GE until 2030 or beyond. Given the total failure of emission reduction so far and the likely continuance of unabated CO2 emissions this would imply the abandonment of the 2ºC mean global temperature rise target which DECC say requires emissions to peak by 2016 and fall thereafter at 3% per year. 

This cautious attitude to GE will also result in missing two advantages of many GE methods - speed and power. There are at least two GE methods that could be applied almost immediately - sulphur dosing of the stratosphere and urban albedo enhancement.

Computer models of sulphur dosing indicate an adverse effect on monsoon rains potentially leading to food shortages for sulphur loading at the emergency intervention level required to counter a doubling of CO2 concentration. However it can be shown that loading at just 10% of that level is sufficient to annul the next 10 years of global CO2 emissions. The lower dosage should reduce the impact on rainfall to manageable levels.

 Urban albedo enhancement is much less powerful but is quicker and cheaper with no known adverse effects. 

I believe that Tim Fox has the better approach when he calls for GE to proceed alongside emission reduction rather than seeing them as alternatives. Whatever we do must be predicated on the obvious failure of emission reduction to even slow the increase in emissions, and must start now.

 Colin Baglin