The Economist blog has a posting about the name calling from both sides of the Global Warming / Climate Change divide. Here is my comment, complete with links.

The name calling will lead to polarized views and more extreme policy. This is why.

There is no balance to all this name-calling. There is abundant evidence that anyone who doubts the Consensus, whether the science or the policy, is vilified. For sceptics, research grants are not nearly as available and sceptical views are more difficult to publish. Any public figure who doubts orthodoxy, or any business which funds scepticism, are targeted by pressure groups. Similarly, scientific groups who do not make strong position statements in favour are targeted by pressure groups and bloggers.

Even if the evidence is over-whelming in favour of there being significant anthropogenic climate change, consider the incentives for a scientist or policy-maker working in the field. The prerequisite for acceptance is singing-up to the main conclusion that mitigation policies are needed to combat likely and severe climate change. To pour doubt on that conclusion risks standing accused of being in the other camp. Novelty comes from restatement of this position in an original way, or from original, and more alarmist research.

It is in the area of policy this bias is most skewed. To check, the Economist should do a benefit-cost analysis, using as a starting point the Stern Review. Stern estimated the likely costs of climate change at 5 to 20 times the mitigation costs*. Then adjust for the more moderate view of climate change outlined in the Economist article in hyperlinked in the article, including a modicum of uncertainty. Then allow for some of the worst impacts (hurricanes, droughts, floods, etc.) are largely speculative. Then allow that some consequences, like sea level rise, will occur over generations. Therefore slow and low-cost adaptation is possible. Then allow for the benefits of temperature and CO2 rise in extending the margins and intensity of agriculture in many areas. Then allow that any politically feasible mitigation policy will be far less comprehensive (on a global scale) than Stern assumed. Then allow that policy choices will be constrained by political realities and that large ill-defined and complex government projects have a tendency to massively over-run on costs and underachieve on benefits – the Economist archive is a good place to verify this supposition.

Well before crunching the final numbers, there will an irreversible tipping-point reached on the benefit-cost analysis. Current mitigation policies will leave future generations worse off than if nothing were done at all. We reach the wrong policy conclusion by letting the issue become polarized.

*The Stern review has some ambiguous statements. The directgov site hyperlinked above says

If we take no action to control emissions, each tonne of CO2 that we emit now is causing damage worth at least $85 – but these costs are not included when investors and consumers make decisions about how to spend their money.  Emerging schemes that allow people to trade reductions in CO2 have demonstrated that there are many opportunities to cut emissions for less than $25 a tonne.   In other words, reducing emissions will make us better off.

But what is clear is that the costs of climate change have been overstated and an extremely naïve assumptions about the efficacy of policy is included.