The Obama administration yesterday released its blockbuster global-warming propaganda document, "Global Climate Change Impacts on the United States." It's a doozy, filled with colour graphics, maps and dramatic pictures. The message: We're all going to climate hell. Action needed now.

Scrolling through the 200-page output reminded me of a funny phrase a policy-wonk friend invented to describe the current state of policy research around the world. He called it, jokingly, "decision-based evidence making." Everybody who hears the phrase cracks up.

The joke, obviously, is a flip version of the slogan "evidence-based decision making," which has been all the rage for years in other fields, notably health care. Google produces thousands of hits for the idea that decisions should be evidence-based.

But the art of policy making has moved on, led by the global warming crusade, which daily produces science reports that turn the original slogan on its head. The new Obama report yesterday joins the Global Humanitarian Forum's recent claim to have found evidence for up to 300,000 annual deaths from global warming (see Peter Foster's article) or the recent MIT climate projections (reviewed here).

Decision-based evidence making isn't a joke. It's part of the plan, the policy, the way things are done.

In 2005, the U.S. National Academy of Sciences, which advises the U.S. Government on science policy, published a book, titled Decision Making for the Environment: Social and Behavioral Science Research Priorities.

The advice in the book is pretty clear: "By focusing scientific efforts increasingly on decision relevance, such a program of measurement, evaluation, and analysis would increase the influence of empirical evidence and empirically supported theory in environmental decisions relative to the influences of politics and ideology .... Processes for determining which research is most decision-relevant should be participatory."

So there we have it. Decision and policy first, evidence later. That, in our book, is pure junk science.