Have we underestimated the challenge?

As a scientist, it's often easy to fall into the trap of thinking about climate change in a purely theoretical manner.  We study the climate system so intensely that its dynamics and physics can obscure the practical and prescriptive challenges that accompany dangerous anthropogenic influence.  If you stop to think about the sorts of changes that would result in a lessening of the radiative forcing attributed to human activity, you quickly realize that they're radical. 

Where is that change going to come from?  Political will?  Market devices?  The limits of our resources?  And furthermore, how much change will be realized in the next ten to fifteen years?  The standard response to these questions invokes political and economic forces as the sole motivator of institutional and individual change.

Until we have a better handle on climate sensitivity or a longer observational record, policy makers will continue look to the projections derived from the special report on emission scenarios (SRES) to construct international agreements.  If those scenarios are off-base, the IPCC may severely err in presenting policy makers with a depiction of the warming associated with the various mitigation avenues available to them.

In this week's edition of Nature, a commentary paper by climate policy expert Roger Pielke Jr., climatologist Tom Wigley, and economist Christopher Green asserts that the IPCC has done just that, underestimate the challenge of stabilizing emissions this century.

The essay's argument relies on the authors' criticism of the spontaneous (without the help of policy measures) energy efficiency improvements built into the IPCC reference scenarios.  This spontaneous improvement varies from scenario to scenario, from two-thirds of the total reduction and up.  They also bring in data showing that current improvements in energy efficiency are already far below the values used in the SRES (the growth of China and India's economies contribute heavily to the global average).  Implicit in their conclusions is the idea that future policy should focus on motivating technological change rather than emission caps.  The Christian Science Monitor picked up on this question, but it is probably a false dichotomy.  The agreements negotiated by the UNFCCC treat a variety of issues: caps, clean development incentives, and conservation measures among them.

As with most of their leading stories, Nature News has a variety of online material to supplement the paper. The Climate Feedback blog gives a nice overview of the practical argument of the paper, as well as some context.  There's also a compilation of reactions from other experts and stakeholders.

I get the feeling this is an academic red herring of sorts.  They've certainly stirred things up, but I hardly imagine that the IPCC is resting on its laurels with respect to the SRES.  Regardless, the amount of uncertainty associated with the scenarios is bound to be large.  After all, Jerome Namias pointed out that the challenge of predicting weather and climate is second to human behavior.  We may run out of cheap fossil-based resources (though not likely...with all the coal and oil shale lying around), making the current SRES an overestimate.

It's particularly hard to cut through to the essential questions and decisions regarding climate change.  Red herrings, false dichotomies, and fallacious arguments are littered throughout the landscape of present conversation over global warming. They serve mostly to distract, rarely and ineffectively raising the level of discourse.

That brings the circle round to scientists, policy makers, and their ability to respectively produce and react to assessments of the state of the climate system and our understanding of it.   If there are aspects of the process and product that are lacking, they must be addressed, but to assert that the methodology is fundamentally flawed goes against years of experience and history.  As Susan Solomon and Martin Manning put it in their recent Science editorial:

"Reformulating the science/policy interface should be considered and be open to change but must acknowledge lessons from the past.  The factors that have been critical to the success of the IPCC need to be preserve if a rigorous scientific basis is to continue to inform the growing challenge of decision-making on climate change."