Climate Models, Uncertainty and Unmade Policy Decisions

I think we’d be remiss to cover the topic of uncertainty without thinking about the role that it plays when scientific research or other forms of data are transmitted from the academic or research realms into the public world of policy debates. As Giles M. Foody notes, problems with uncertainty “can lead to a resistance against calls for changes because of the uncertainties involved” (114). I think he’s right but this is a vast understatement.

In the climate change debate now swirling through most of the globe, uncertainty could be described as one of the main factors propelling so-called climate skeptics, naysayers and those generally unwilling to acknowledge that human energy consumption might be influencing the global climate. Just take a look at this skeptic’s blog post. He names uncertainty in climate science as the number one reason not to move too fast on this global, vexing issue. In fact, much of the opportunity for debate on the issue stems from varying points of view on just how certain the hundreds and thousands of climate models out there might be in predicting a warming world. In fact, just try Googling “climate” and “uncertainty” and you’ll find an avalanche of information – some more scientific than others.

Foody does a nice job of summarizing this paradigm when he writes about how “end-users and decision-makers often fail to appreciate uncertainty fully” (115). I couldn’t agree more. What most climate scientists will tell you is that while their models contain a great deal of uncertainty – which varies depending on what type of model your discussing or how it’s been parameterized – the overall trends are pretty clear. Most of the work done in this field concludes that a relationship does, in fact, exist between CO2 emissions and a warming global climate. Yet the importance of uncertainty, here, lies not within the scientific community but with publicly debated policy decisions where uncertainty/error can conveniently become a political football. I mean just look at some of the variation in predictions from climate models in the IPCC’s 2001 report:

Figure 1. A selection of climate models and their prediction of globally averaged surface air temperature change in response to emissions scenario A2 of IPCC Special Report on Emission Scenarios. CO2 is ~doubled present concentrations by year 2100. Figure reproduced from Cubasch et al. (2001).

Yes, there’s some definite variation between models, a degree of uncertainty. But how does this compare with the idea we discussed in class about scale. Can we ever expect to have complete accordance and certainty amongst climate models when the issue operates on such a vast, global scale? Should we expect it on smaller, regional scales with something as complex as the atmosphere’s inputs and ouputs and the sun’s radiation?


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