Today Phil Plait decided it would be fun to start a firestorm by discussing denialism, in particular with respect to global climate change. Of course the denialists chimed in, always fun.
But reading (and commenting) at BA it is clear it doesn't matter how much evidence is created towards demonstrating climate change is real. The same old canards come up. Economy will get ruined. No evidence for Global warming. Ok, evidence for Global warming but no evidence that humans have anything to do with it. etc etc.
It made me realize what a denialist is.
Someone who asks for evidence but expects proof.
What inevitably happens is that someone claims "No evidence for AGW" and you will present lots of evidence like CO2 absorption bands, upper stratospheric cooling, and a host of other things, and they may read it (or not) and simply claim "No evidence!" afterwards. They are expecting proof and if no proof is given, then no evidence is good enough. This is a form of the Nirvana Fallacy, as related to scientific study. The proof of the claim has to be perfect before any of the supporting evidence can gain any validity.
They fail to understand the concept of conditional proof of which all science is based upon. Newton "proved" out his laws of motion, and he was right, until Einstein came along and "proved" that Newton was inaccurate (as opposed to wrong). Einstein didn't even have good evidence other than paper studies until the Michelson-Morley experiments were completed. Even those didn't prove out relativity, they gave a lot of evidence supporting the theory. the new theory has to encompass the existing data. The new theory will usually be a superset of the existing inaccurate one.
There is now a lot of compelling data for the hypothesis that man is spewing too much GHGs into the atmosphere. Other theories like that it is natural Malinkovich cycles, sun and cosmic ray fluctuations, and other have been posed, argued, defended, and put away. One of the compelling arguments for the GHG as a significant factor is the fact that the physics based models depicting previous data (these aren't line fits), require the additional forcing of artificial release of GHGs to match as well as they do. I have yet to see a single denialist show that a physics based model can match historical data as well as these but leave out the GHGs.
But what a denialst will see when they look at a series of graphs like that is that they don't match perfectly. Newsflash, models never match actual data perfectly for three main reasons:
- Historical data has error in its measurements
- Models don't contain every single minor mechanism or they have approximations of some mechanisms
- Transient events happen that affect the models (like the el Nino in 1998)
But a denialist won't care. It's not perfect and therefore its useless. Meanwhile we have similar inaccuracies in modeling rocket launches but that goes Ok. We model cars and performance before we build them, and that seems to work out OK. We model chemical processing plants before sinking 100 millions into building one. Modeling as part of science is a tried and true method by which to learn about a subject. It allows for faster evaluation of "what if" scenarios and don't need to have absolute precision to be useful and reliable.