There is a new paper which raises questions about the ability of the IPCC global climate model to skillfuly predict paleoclimate. The IPCC has claimed such skill as evidence of its skill to predict climate decades into the future. Based on this new paper, such a claim is unwarranted.
Paul Valdes, 2011: Built for stability. Nature Geoscience Volume: 4, Pages: 414–416 DOI: doi:10.1038/ngeo1200 Published online26 June 2011
The article has the headline text
“State-of-the-art climate models are largely untested against actual occurrences of abrupt change. It is a huge leap of faith to assume that simulations of the coming century with these models will provide reliable warning of sudden, catastrophic events.”
His text includes
“I argue that climate models of the current generation, as used in the latest assessment of the Intergovernmental Panel on Climate Change (IPCC), have not proved their ability to simulate abrupt change when a critical threshold is crossed. I discuss four well-documented examples of past rapid climate change (Box 1). In two cases, the models did not adequately capture the basic climate configuration before abrupt change ensued, and in the remaining two examples, to initiate abrupt change the models needed external nudging that is up to ten times stronger than reconstructed. The models seem to be too stable.”
“In the meantime, we need to be cautious. If anything, the models are underestimating change, compared with the geological record. According to the evidence from the past, the Earth’s climate is sensitive to small changes, whereas the climate models seem to require a much bigger disturbance to produce abrupt change. Simulations of the coming century with the current generation of complex models may be giving us a false sense of security.”