Thursday :: Apr 10, 2008

Seriously Underestimated


by Turkana

In the April 3 edition of the science journal Nature, Roger Pielke Jr., Tom Wigley, and Christopher Green offer a warning that accords with the recent assessment by James Hansen, who believes the need to cut carbon dioxide emissions is greater than many understand:

The United Nations Climate Conference in Bali in 2007 set the world on a two-year path to negotiate a successor to the 1997 Kyoto Protocol. Yet not even the most rosy-eyed delegate could fail to recognize that stabilizing atmospheric carbon-dioxide concentrations is an enormous undertaking. Here we address the magnitude of the technological changes required to meet that challenge. We argue that the size of this technology challenge has been seriously underestimated by the Intergovernmental Panel on Climate Change (IPCC), diverting attention from policies that could directly stimulate technological innovation.

The IPCC uses 'reference' scenarios of future emissions that assume no policy interventions directed towards reducing greenhouse-gas emissions (notably carbon dioxide) to determine the magnitude of additional emissions reductions ('mitigation') needed to stabilize atmospheric carbon-dioxide concentrations at various levels. It is on these additional reductions that policy-makers have focused most attention.

Here we show that two-thirds or more of all the energy efficiency improvements and decarbonization of energy supply required to stabilize greenhouse gases is already built into the IPCC reference scenarios. This is because the scenarios assume a certain amount of spontaneous technological change and related decarbonization. Thus, the IPCC implicitly assumes that the bulk of the challenge of reducing future emissions will occur in the absence of climate policies. We believe that these assumptions are optimistic at best and unachievable at worst, potentially seriously underestimating the scale of the technological challenge associated with stabilizing greenhouse-gas concentrations.

Pielke Jr. is in the Center for Science and Technology Policy Research, University of Colorado, Boulder. Wigley is in the National Center for Atmospheric Research, Boulder. Green is in the Department of Economics, McGill University, Montreal.

Turkana :: 7:34 PM :: Comments (20) :: Digg It!