The lead post on Watts Up With That (WUWT) is one called help launch climate skeptic film project: 50 to 1. The post is asking for financial support for an Australian film project that aims to show that trying to stop climate change is 50 times more expensive that simply adapting to it. Okay, so I think these kind of claims are extremely dangerous, but let’s simply look at the calculation that is being used to make this claim.
The calculation was done by one Lord Christopher Monckton. Many would regard this alone as sufficient evidence to suggest that it is nonsense, but let’s carry on regardless. To be fair, I can’t see any particular error in his arithmetic. What does he do? Well the calculation is based on the proposed Australian CO2 tax. The claim is that, at best, it will reduce emissions by 5%. Australia only contributes 1.2% of world emissions and hence the reduction will be tiny. Given this reduction one can use an estimate of climate sensitivity to determine how much it will reduce the possible temperature rise. This again is tiny according to Christopher. One can then determine, based on this, the cost per oC abated. If we wish to use this to prevent a 0.17oC rise over the next decade we can then estimate the cost which turns out to be $420 trillion. Given that world GDP is about $80 trillion, this is 80% of world GDP over 10 years.
The next step is a claim that simply adapting to climate change would cost about 1.5% of world GDP and hence is 50 times cheaper than trying to stop it from happening in the first place. There should be some obvious problems with this. Even if this carbon tax is initially ineffective, the effect is likely to be non-linear. It might be expensive in the beginning, as most new technologies are, but would presumably become cheaper with time. The other problem is that we can’t really know the cost of adapting. I’m sure someone has suggested that 1.5% of GDP would be enough, but we can’t know if this is a good estimate or not.
There is, however, a much more fundamental issue with this calculation. It’s based on an Australian carbon tax which will raise $13 billion per year. Australian GDP is about $1.3 trillion, so the tax will raise 1% of Australian GDP. If extended to the rest of the world, surely it would simply be 1% of world GDP. It might not be effective (as claimed) but it can’t ever get to the stage of being 80% of world GDP. Furthermore, if it does turn out to be ineffective, wouldn’t we simply spend it on adapting. Given that adapting to climate change is projected to cost 1.5% of GDP, this might be slightly too little, but it’s close. At worst, the ratio would be 1:1, not 50:1. We wouldn’t continue to try and use a carbon tax to reduce temperatures if it’s not working. We’d use this to adapt as suggested here. There may well be valid issues with this carbon tax idea, but suggesting that it’s 50 times less effective than the poorly understood cost of adapting seems absurd. Furthermore, doesn’t it seem better to try and prevent climate change rather than simply do nothing and hoping that those who claim that we can simply adapt in the future are correct.