Just a quick post to highlight a BBC article called society set for climate change woe. You might be surprised by who was quoted as agreeing that we are about at the point where the consequences are starting to outweigh the benefits. It’s the same person who has just published a paper suggesting an anthropogenic signal in economic losses from hurricanes.
My main reason for writing this was to comment on a quote from Matt Ridley. It might qualify as the highest density of errors seen to date. He says
I think we probably will see 1.5 degrees of warming. The point is most people think 2C is when it turns catastrophic. That’s not right. The literature is very clear; 2C is when we start to get harm. Up until then we get benefit.
We’ve just passed 1oC. Warming is expected to depend linearly on cumulative emissions. We’ve emitted about 550GtC to date, and are going to find it very difficult to not come close to doubling this. The only way we could only see 1.5oC of warming is if we do suddenly start reducing our emissions, or if the anthropogenic contribution to date is much smaller than we currently think.
Well, we’re pretty certain that more than half of our recent warming is anthropogenic and the best estimate for the anthropogenic contribution is more than all of it. I guess Ridley is welcome to think that we’ll probably see 1.5oC of warming, but if he does it just illustrates that he’s rather clueless about a topic that he’s written about for a number of years. Most now think that staying below 2oC is getting increasingly difficult.
The 2oC boundary is also not when we think it will turn catastrophic. At best it’s perceived as a limit that keeps us well away from the level of warming that might justifiably be described as catastrophic. It’s also not clear that 2oC is when we start to get harm. It’s a continuum; there’s not some kind of actual boundary below which everything is good and above which things get bad. Also, it is likely that the damages will be non-linear. The difference between 2.5oC and 2oC is likely to be considerably greater than the difference between 2oC and 1.5oC.
It’s also not true that the literature is very clear. The only study I’m aware of that suggests that there might be benefits for some future warming is Richard Tol’s 2009 meta-study. Not only were most of those benefits sunk anyway, he’s since corrected his study to show that there are virtually no benefits for future warming. Tol’s study has also been quite heavily criticised.
So, as far as I can tell, virtually every sentence of Ridley’s comment is essentially wrong. Quite remarkable really; I didn’t think he could get even more wrong than he’s been before. Maybe I shouldn’t be surprised though; this is someone can write an article on libertarianism and the distrust of elites without mentioning that he’s a Viscount.