1. Its all models Well obviously the measurements of the current temperature rise aren't (except the ones from the satellites, which do have to be passed through a model, ha ha, so its ironic that the same people who will argue "its all models" tend to prefer the satellite record...), nor are the observed rise in GHG's. But projections of future change inevitably come through models. But these models are themselves constrained by observations (match to the past century) and theory (basic radiative transfer; feedbacks; etc).
Consensus science is not science. Incredibly, some people are capable of arguing something along the lines of:
- Science is not done by consensus
- There is a consensus on X
- Therefore, X is wrong.
This is obviously silly. It is true that science isn't done by consensus - but so what: no one is saying it is. But when you're thinking of science advice to policy making, you ought to follow the consensus/majority view.
I've sort-of done this before.
3. All the scientists say the same thing because otherwise they will lose their jobs. This one fails to explain the existence of skeptics like Lomborg, Lindzen, Spencer or Svensmark. And it fails completely to understand the nature of scientific society. It isn't some kind of Sekret Kabal. Its an open process: if there are holes in a theory, you can make a name for yourself by pointing this out. I would say that consensus-busting papers stand more chance of being published (on an assumption of equal technical merit) than those supporting it: purely because of the requirement for novelty which journals impose.
4. Water vapour is the dominant greenhouse gas. Well no, it isn't (since I blogged this myself, I'm embarassed to have forgotten it). Its the submissive GHG :-)
5. CO2 saturates within 1m/10m. This one is fairly technical so not very popular as a myth, because it requires a bit to even understand it. The idea is that increasing CO2 won't matter, because the CO2 absorption regions are saturated anyway. Now this isn't one of my strong points (Josh?) but as I understand it this is why the radiative response to CO2 is linear (v low CO2 levels) to sqrt (moderate) and log (current levels).
6. There are not enough fossil fuels available to increase CO2 levels. This one is fairly rare and I'm not sure anyone really believes it. Oil might run out but I don't think there is any shortage of coal, tar sands and misc gunk to get us to at least four times pre-industrial CO2. I find it hard to believe that the future emissions scenario constructers failed to consider this point.
7. Its all the sun. Solar forcing has probably increased over the last century, but as far as can be told its small compared to GHG's. And it has (I think) decreased recently (last few decades)). The solar stuff tends to rely on correlations, whose significances are hard to assess - because the std statistical analyses rely on you doing the assessment once, not on keeping searching for things to correlate till you get a result. Mention here for Paul Farrars work on aliasing of ENSO onto the cloud signal, and the changing-their-minds stuff about polar or mid-latitude clouds. And the bit about the dodgy numbers at the ends of the record (Laut?). Sorry: life is hell without a proper connection...
8. Its all hype to get funding. This one has a grain of truth to it. Agencies do tend to look favourably on proposals which are relevant to the real world. Amusingly, this is probably why a number of solar type folk have got interested in GW and are pushing the solar-GW connection: its good for funding. Which shows up the converse: of the skeptics, plenty have tenure; plenty of tenured people aren't skeptics. But if you want large funds and high salaries... you don't go into science to start with, or stay there.
9. CO2 lags temperature in cores. In facts its pretty hard to tell whether is does or not, because the CO2 comes from the air trapped in the bubbles but the temperature signal comes from the ice itself. And this leaves an uncertainty as to the age of the CO2 relative to the ice, because the pores in the ice only close off slowly - leaving uncertainties up to about 800 y in high cold cores like Vostok. And when you're plotting picture to play with the data yourself, its hard to know what adjustments have been made, so be careful. However, having said that, I think that what indications there are do tend to indicate temperature leading CO2. But: this is not terribly relevant. Trying to explain the last 800 kyr of ice ages, there is a puzzle as to the size of the forcing, which needs an amplifier to produce the size of response. CO2 feedback is one candidate. In which case, you would expect T to lead CO2. But in the case of current climate change, we know full well that the forcing is CO2, not temperature.
10. Fred Singer has anything useful to say about global warming. The traditional number 10: not one that many people believe. Did you know that of those listed on the board of advisers to SEPP, three are dead? Play a fun game: see if you can guess which they are (no cheating by looking at the wiki page).