For sale: Doubt.

"Doubt is our product"  Internal memo, Brown & Williamson (subsidiary of British American Tobacco), 1969.

Science is hard! I know, dude, from experience. And climate science is really hard! It takes thousands of clever people and huge expense, but great work is being done. Uncertainties remain, however, and they always will.

Denying, or casting doubt on, science is a piece of piss in comparison. Whether it is the health effects of tobacco or DDT, or the severity of acid rain, the ozone hole or anthropogenic global warming, doubt is a commodity, and it is serious business.

U.S. science historian Naomi Oreskes, currently on an Australian tour promoting her new book Merchants of Doubt: How a handful of scientists obscured the truth on issues from tobacco smoke to Global Warming (coauthored with Eric Conway), laid out the tricks in a few simple dot points at her recent presentation at the State Library of Victoria. She calls this "the tobacco strategy", as it was in the arena of big tobacco vs science that these skills were honed by men such as those who founded the George C. Marshall institute and later became key players in the climate change denialist industry. She lists five simple tricks:

1. Cherry picking
2. Using data out of context
3. Personal attacks
4. Pressuring journalists to "publish the other side"
5. Finding the tiny handful of dissenting scientists and promoting the hell out of them

And that pretty much covers every argument you will ever hear a global warming denialist make, although I would add a sixth: lying.

To be clear, the facts of global warming are pretty much beyond reasonable doubt, and many of them are not at all new: 1850s, John Tyndall establishes that CO₂ is a greenhouse gas; early 1900s, Svante Arrhenius postulates that burning fossil fuels could increase atmospheric CO₂ and lead to global warming; 1960s, confirmation that atmospheric CO₂ concentrations are increasing; 1979, a consensus position of the U.S. National Academy of Sciences that

Climate change will result from man's combustion of fossil fuels and changes in land use.

And that statement holds true to this day (although it should be changed to "climate change is resulting..."), even though many of the details are still a little vague. As Oreskes puts it

There are big trees of uncertainty in a forest of robust scientific certainty.

What can you see?