SRM: Surface methods

The final approach considered under the category of SRM geo-engineering is that of increasing surface albedo.  This blog won’t be overly extensive as there a re a few fundamental limitations to this concept that negate the need (as well as the ability) to fully critique it.

Increasing the surface albedo is a method that proposes doing exactly what it says on the tin.  Though, since the Earth is not one uniform surface there are several ways in which this could be achieved (Royal society, 2009):

• Whitening roofs, road and pavements in urban settlements

            - cost: 1% of earths land surface $300 billion per year

• Increase more reflective crop varieties

            - cost: unknown

• Installing reflective materials into the desert

            - cost: $ trillions per year and extensive ecological consequensces.

• Reforestation

            - cost: unknown

The overlying issue with these techniques is their inefficiency (relative to cost!) compared to other SRM methods.  What has become apparent as I’ve been blogging it that SRM methods closer to earth are less efficient and more limited in reducing global temperatures whilst having a much more significant regional or local climate signature.  This area of SRM is no different, and would likely have the greatest regional impacts and the smallest overall global climate forcing concordant with its direct implementation on the Earth itself. 

In order to achieve the adjusted albedo necessary to correct global warming, extensive resources and investment would be required due to the shear spatial extent at which such methods would need to be implemented.  This also poses another problem, there are limitations to how far the earths surface albedo can be significantly altered (arguable some of the above options would exceed what is reasonable!), as such, with climate continuing to warm, this method, like cloud whitening, has a use-by date dicatated by our climbing CO2 levels.

The literature surrounding these methods falls short of some of the previous SRM approaches.  Perhaps this should be considered to be representative of the lack of support in these areas due to their ineffective and unfeasible nature.

Conclusion

Regardless of the individual environmental impacts of each of these methods (which regionally would be quite significant!), these methods are fundamentally limited by their inability to effectively and fully achieve the desired level of global climate cooling.