What can we learn from climate models?There's a great deal more in her post. Go read the whole thing.
Posted on October 3, 2010
by Judith Curry
Short answer: I’m not sure.
I spent the 1990’s attempting to exorcise the climate model uncertainty monster: I thought the answer to improving climate models lay in improving parameterizations of physical processes such as clouds and sea ice (following Randall and Wielicki), combined with increasing model resolution. Circa 2002, my thinking became heavily influenced by Leonard Smith, who introduced me to the complexity and inadequacies of climate models and also ways of extracting useful information from weather and climate model simulations. I began thinking about climate model uncertainty and how it was (or rather, wasn’t) characterized and accounted for in assessments such as the IPCC. A seminal event in the evolution of my thinking on this subject was a challenge I received at Climate Audit to host a thread related to climate models, which increased my understanding of why scientists and engineers from other fields find climate models unconvincing. The Royal Society Workshop on Handling Uncertainty in Science motivated me to become a serious monster detective on the topic of climate models. So far, it seems that the biggest climate model uncertainty monsters are spawned by the complexity monster.
This post provides my perspective on some of the challenges and uncertainties associated with climate models and their applications. I am by no means a major player in the climate modeling community; my expertise and experience is on the topic of physical process parameterization, challenging climate models with observations, and extracting useful information from climate model simulations. My perspective is not in the mainstream among the climate community (see this assessment). But I think there are some deep and important issues that aren’t receiving sufficient discussion and investigation, particularly given the high levels of confidence that the IPCC gives to conclusions derived from climate models regarding the attribution of 20th century climate change and climate sensitivity.
I don’t think we can answer the question of what we can learn from climate models without deep consideration of the subject by experts in dynamical systems and nonlinear dynamics, artificial intelligence, mechanical engineers, philosophy of science, and probably others. I look forward to such perspectives from the Climate Etc. community.
The issue of model verification and validation (V&V) is well known in the modelling community. (Here's a fairly standard presentation on it.) But apparently V&V isn't well known or well understood in the climate modelling community. Consequently they have set the world off on a many billion dollar (and soon-to-be trillion dollar) fiasco. They have disrupted economic growth (and force the starving poor to die) while these fanatics strive to "out green" each other in their zealotry to shut down economic growth to "save Mother Earth" from a (most likely) non-existent problem. This won't be the first time in human history when zealots have disrupted a society and imposed their fanatic views on others. But as the world has become globalized, the danger from fanatics like the "global warming" crowd or the Al Qaeda religious fundamentalists are becoming overwhelming. Fanatics can derail societies.