Today I came across two views of the role of science in politics presented by two very distinguished scientists. The first, Harvard’s John Holdren, tells us that:

The science of climate change is telling us that we need to get going.

The notion that science tells us what to do leads Holdren to appeal to authority to suggest that not only are his scientific views correct, but because his scientific views are correct, then so too are his political views.

Members of the public who are tempted to be swayed by the denier fringe should ask themselves how it is possible, if human-caused climate change is just a hoax, that:

The leaderships of the national academies of sciences of the United States, Britain, France, Italy, Germany, Japan, Russia, China, and India, among others, are on record saying that global climate change is real, caused mainly by humans, and reason for early, concerted action.

This is also the overwhelming majority view among the faculty members of the earth sciences departments at every first-rank university in the world.

All three of holders of the one Nobel prize in science that has been awarded for studies of the atmosphere (the 1995 chemistry prize to Paul Crutzen, Sherwood Rowland, and Mario Molina, for figuring out what was happening to stratospheric ozone) are leaders in the climate-change scientific mainstream.

U.S. polls indicate that most of the amateur skeptics are Republicans. These Republican skeptics should wonder how the presidential candidate John McCain could have been taken in. He has castigated the Bush administration for wasting eight years in inaction on climate change, and the policies he says he would implement as president include early and deep cuts in U.S. greenhouse-gas emissions. (Barack Obama’s position is similar.)

The extent of unfounded skepticism about the disruption of global climate by human-produced greenhouse gases is not just regrettable, it is dangerous. It has delayed – and continues to delay – the development of the political consensus that will be needed if society is to embrace remedies commensurate with the challenge.

By contrast, Robert Lackey a career scientist at EPA, paints a very different picture:

Recently I presented a talk to a group of community activists about why salmon populations along the West Coast have dropped to less than 5% of their historical levels. I’ve given such talks many times so I was confident that I had heard just about every question that might be asked. I was wrong.

The opening question was asked by a well known political activist. He was direct, pointed, and bursting with hostility: “You scientists always talk about our choices, but when will you finally tell us what we SHOULD do about the dramatic decline of West Coast salmon? Quit talking about the science and your research and tell us what we should do! Let’s get on with it!”

From the nods of approval offered by many in the audience, his impatience with science and scientists was broadly shared. . .

In a pluralistic society, with a wide array of values and preferences competing for dominance, the ecological policy debate is usually centered around whose values and preferences will carry the day rather than over scientific information.

So what was my answer to the emotionally charged question from the political activist? It was: “Science, although an important part of policy debates, remains but one element, and often a minor one, in the decision-making process. We scientists can assess the ecological consequences of various policy options, but in the end it is up to society to prioritize those options and make their choices accordingly.”

He wasn’t pleased.

If you are a scientist, then you have to figure out what you think about the relation of science in policy and politics. If you think that science compels political outcomes then you will follow the lead of John Holdren. If you think that science does not compel political outcomes, then you’ll follow the lead of Robert Lackey. But you do have to choose.

My advice? See what scholars of science in policy and politics have to say about this question, and make an informed decision. One of these distinguished scientists has views consistent with the consensus view of relevant experts, and one does not.