To follow up from my earlier post I thought I might quickly write another one, as it almost seems as though Richard Tol has forgotten that he published – last year – a correction to his own 2009 meta analysis.
In his 2009 meta analysis, the figure on the right appeared. In today’s BBC article, Matt Ridley says:
The literature is very clear; 2C is when we start to get harm. Up until then we get benefit
Which appears to be based on Tol’s 2009 paper.
In Tol’s 2014 correction the figure on the left appears. Now, unless I’m missing something, this would seem to no longer be consistent with a suggestion that it is only 2C when we will start to get harm.
In this Bishop Hill post, however, Richard Tol says:
Matt and I disagree on many things, but not here: Matt referred to the point were the impact turns negative (about 2K), I referred to the point where the incremental impact turns negative (about 1K). You can also refer to the point where the impact turns significant and negative (about 4K).
So, has Richard forgotten his correction to his own paper?
I’ll also leave it as an exercise for the reader to discover whose study produced about the only positive data point (some of the ones near 0 are – I think – just positive), located at +2.5 for 1oC of warming.