I really thought that maybe Watts Up With That (WUWT) was keeping quiet about Topher Field’s 50-to-1 video project because they’d realised just how silly the actual calculation was. Oh, how wrong I was. There is now a new post claiming that the ratio really should be 100-to-1.
For those who don’t know, Toper Field’s 50-to-1 project was based on a calculation claiming that the cost of mitigating against climate change was 50 times more expensive than doing nothing and simply adapting to climate change if and when it happens. It is a very silly calculation (initially done by one Christopher Monckton) which I’ve discussed before. It’s also been debunked by Michael Tobis. The new post on WUWT seems to be claiming that because the Equilibrium Climate Sensitivity (ECS) is likely to be lower than previously thought, one can show that the actual ratio is more likely to be 100-to-1.
I’m not going to say much more because debunking this is actually quite trivial. It is based on an assumption that a carbon tax of 1% of world GDP would reduce CO2 emissions by 5%. Simplistically, therefore, the most this could ever be is 20% of world GDP (and even that is wrong because as CO2 emissions reduce, the tax revenue will drop). The other assumption is that adapting to climate change will cost about 1.5% of world GDP (probably wrong, but that’s the assumption used). Therefore, in a simple sense, the most the ratio could ever be is about 13-to-1. So, changes to ECS do not really influence this calculation at all given that it is based only on the reduction in CO2 emissions, not on the reduction in temperature. Michael Tobis actually argues that a calculation using consistent information actually results in it being 12.5-to-1 in favour of mitigation.
I, however, don’t really know if any of these types of calculation can be done with any real rigour. The uncertainties must be very large. I do know, however, that Topher Field’s calculation and the new WUWT one are both nonsense.