Two recently published articles underscore the need for aggressive funding of solar geoengineering research, including field experiments, as quickly as possible. The first, by Valerie Livina and Tim Lenton, presents a convincing case that the Earth has already passed a planetary tipping point, namely, the cratering of Arctic sea-ice volume and extent widely reported in summer 2007. According to the authors, this contraction marked not only a record low (since surpassed--see Call for Immediate Arctic Deployment Dismissed by UK Parliamentary Committee, 9/24/12), but a transition to a new, reduced, less stable state. Data since 2007 suggest that sea-ice has shifted permanently to this new equilibrium--as Lenton describes it, "This wasn't a one-off, it was a permanent change."
The second study affirms recent climatic changes but also highlights the ameliorative potential of stratospheric aerosols. A team at the University of Colorado Boulder has demonstrated that sulfur emissions from relatively small volcanoes worked to suppress global average temperature increases between 2000 and 2010. Approximately one quarter of the warming that would have taken place over this period was likely offset by sulfate aerosols in the stratosphere derived from these eruptions. "This new study indicates it is emissions from small to moderate volcanoes that have been slowing the warming of the planet," says lead author Ryan Neely. Mount Pinatubo in the Philippines, by comparison, is regarded as a large volcano.
Meanwhile, the sequester has struck Washington, and there is no new information on possible geoengineering research funding (see Obama Administration Considering Possible Research Funding, 1/29).