Easy, just 'follow the money'. Everyone knows that funding source makes the difference, right? So science done during the Bush years is not valid if you are a Democrat and likewise for science done during the Obama years for Republicans.
But that isn't really true. Union of Concerned Scientists spends more in one year promoting climate change than Exxon has spent in its history denying it; is UCS just a cynical fundraising group advocating the latest pet causes? Maybe, but getting donations is not evidence of that.
John Timmer, writing at Ars Technica, dissects the latest 'follow the money' claim, this one contending that the only way to get funding is to be on the climate change bandwagon for the government - yet we know that isn't true. During the Bush years, Dr. James Hansen flew all over the world at taxpayer expense giving talks about global warming - and he got about a million bucks in fees to do it - but that would not be possible if the government were micromanaging science funding and scientists based on the pet beliefs of presidents.
Obviously it is not just right wing climate skeptics who think scientists are for sale to anyone writing a check; left-wing people believe the exact same thing about scientists at, for example Monsanto - you can't be at Monsanto unless you want to poison the Earth. Well, then that would mean you can't be in earth science academia getting funding from grant agencies unless you are toeing the climate change line. The logic doesn't add up.
And, as Timmer shows, the numbers don't add up either.
Accusations that climate science is money-driven reveal ignorance of how science is done by John Timmer, Ars Technica