The BBC has continued with its goal of always including someone associated with the Global Warming Policy Foundation in any segment on climate science. This morning it was Nic Lewis on Radio 4. The segment starts about 15 minutes in, and is actually okay. It mainly focuses on Nic Lewis’s recent work, and the apparent convergence of the views of “skeptics” and mainstream scientists. Apart from Roger Harrabin confusing doubling CO2 concentrations and doubling CO2 emissions, he does a pretty good job of describing the situation. Even though Nic Lewis’s work does suggest that climate sensitivity is lower than other estimates suggest, there is a large overlap and they aren’t as inconsistent as some might have you believe.
Nic Lewis doesn’t say much, but does do the standard climate models running too hot. This is clearly a possibility, but it is really too early to know, and they aren’t the only reason that we think equilibrium sensitivity is around 3oC per doubling of CO2. There are also a number of reasons to think that Nic Lewis’s recent work may be underestimating climate sensitivity. I’ve discussed this before, so don’t want to go into great detail again. There are, however, some things to bear in mind.
- The energy budget method used by Nic Lewis – although useful – is quite simple and can’t capture all the complexities of the climate system, such as inhomogeneities in the forcings or non-linearities in the feedbacks.
- Similarly, these energy budget methods do not capture slow feedbacks.
- Even though Nic Lewis’s work implies that climate sensitivity might be lower than other methods suggest, there are recent adjustments to the surface temperature record and the ocean heat content (not considered by Nic Lewis) that would increase these estimates.
- Nic Lewis’s results do not exclude the possibility of the equilibrium sensitivity being higher than 3oC, or the transient response being close to 2oC.
- Even though these energy budget estimates do use observations, they still rely on results from models.
So, if climate sensitivity is on the low side (which is a possibility, even given the IPCC estimates) then we would have more time and our inaction today may not do as much damage as it would were it higher. However, if it’s not low (and even Nic Lewis’s work allows for this), and we follow a high emission pathway, there is a possibility that we could have 2oC of warming, relative to pre-industrial times, within the next 3 decades. It would be great if climate sensitivity is low. However, if we do assume that it is, and we turn out to be wrong, our error will be apparent very soon.
The segment also mentioned climate skeptic and influential blogger Andrew Montford. Well, if he keeps promoting – without comment – dross like this on his site, then I don’t think climate skeptic is the correct descriptor. Essentially, though, this BBC segment on climate science only mentioned two people, both of whom are associated with the Global Warming Policy Foundation (GWPF). I’m actually struggling to think of a single BBC segment on climate science in the recent past that has not had at least one person associated with the GWPF. Here’s a challenge to the BBC. Why not have something on climate science that does not include someone from the GWPF. I’m not suggesting excluding them completely, just suggesting that there are many other organisations who would be (more?) suitable. With all due respect to Nic Lewis, if all you’re looking for is a climate scientist with a few publications who would be willing to speak to the media, there are hundreds of candidates. Of course, if you’re looking for one who is willing to argue against the mainstream position, the pickings may be slightly slimmer.