Levi, B. G., 2008: Will desperate climates call for desperate geoengineering measures? Earth scientists ponder the wisdom of large-scale efforts to counter global warming. Physics Today, 61:8, 26-28.
Excerpts of the article read
“Concerned that Earth’s climate will change to an unacceptable degree or at an unacceptable rate before economies can shift significantly away from carbon-based energy sources, some scientists have begun casting their eyes in a previously shunned direction: geoengineering, or intentional and large-scale intervention to prevent or slow changes in the climate system.
Geoengineering sometimes refers strictly to techniques for increasing Earth’s albedo, or reflectivity, to lower its temperature and compensate for greenhouse warming. More broadly, the term can include efforts to accelerate some of the natural processes for removal of CO2 from the atmosphere. Many such ideas have been around for decades. In the past few years, however, the debate over their potential deployment has intensified.”
The figure below, reproduced from their paper (unfortunately, the image is poor), presents different geoengineering approaches and their relative costs and risks.
(Figure originally from Kurt House, Harvard University.)
Each of these porposals for geoengineering of climate, however, are fraught with very significant risk!
As discussed in an early Climate Science weblog What is the Importance to Climate of Heterogeneous Spatial Trends in Tropospheric Temperatures?
“…..regional diabatic heating due to human activities represents a major, but under-recognized climate forcing, on long-term global weather patterns. Indeed, this heterogeneous climate forcing may be more important on the weather that we experience than changes in weather patterns associated with the more homogeneous spatial radiative forcing of the well-mixed greenhouse gases…”
The proposed options of geoengineering of climate illustrated in the figure would result in new human heterogeneous climate forcing. Since we do not even yet know the consequences of the existing inadvertent non-homogeneous human climate forcings such as land use/land cover change and aerosols (i.e. see), the introduction of deliberate heterogeneous human climate forcings is dangerous and irresponsible.
The claim in the Levi Physics Today article that geoengineering “intervention” [can] prevent or slow changes in the climate system is completely wrong. Geoengineering would cause changes in the climate system! The Levi focus almost exclusively on the role of the addition of carbon dioxide into the atmosphere is blind to the importance of altering the spatial pattern of climate forcing as a result of geoengineering.