I understand Jason’s intent in his post about ideologues, and I agree (almost) without reservation that environmentalism needs to stay firmly in the realm of reality, facts, and evidence while eschewing fantasy, whims, and delusional optimism — or, for that matter, delusional pessimism.

However (you knew that was coming) …

Given the deluge of bad news we see every week coming from reputable scientists — for example, that the Northwest Passage is still ice-free in late October — many if not most environmentalists would agree that the burden of proof has been met. We have already “locked in” a certain degree of warming, and Australia — to take a modern, western state as our example — is already suffering greatly. Whatever fraction of Australia’s fate you believe is due to natural variation, it is inconceivable that continued CO2 emissions will improve matters.

Add to this the description from the Guardian of the upcoming report on climate change from Sir Nicholas Stern, former Chief Economist to the World Bank and now advisor to Tony Blair’s government in London:

Grist thanks its sponsors. Become one.

The economist Sir Nicholas Stern’s report on climate change will paint an apocalyptic picture over 700 pages of where global warming could lead, arguing that, unless we act, it will cost more than two world wars and the Great Depression of the Thirties and render swaths of the planet uninhabitable. Even if the world stopped all pollution tomorrow, the slow-growing effects of carbon already pumped into the atmosphere would mean continued climate change for another 30 years – with sea levels rising for a century.

Nor, he will say, is unilateral action by one country enough: if Britain closed all its power stations tomorrow, within 13 months China would fill the gap left in global emissions. Given that the effects will be felt around the world – from the collapse of the Amazonian rainforest to the melting of Greenland’s ice sheet and changes in the Indian monsoon – the response must be global, too.

Grist thanks its sponsors. Become one.

Now, I don’t think for a second that Jason is ignoring these kinds of stories, but to him (please, Jason, correct me if I’m misinterpreting you ) it’s not yet enough to justify the costs of massive CO2 reductions. (Here I’m conceding the argument that reducing CO2 emissions is costly, something I don’t in fact believe.)

In order to stave off the worst effects of massive climate change, there’s no alternative to massive reductions in our emissions of carbon dioxide. It’s not that I enjoy the expansion of taxes and state power likely in this scenario, or that I think western civilization is decadent and needs to be purged, but because — having read continuously on this matter for almost a decade — I don’t believe incrementalism can work anymore.

If we’d taken the earliest warnings of climate change seriously in the mid-1980s, incrementalism might have been sufficient. Two decades later … not so much. Perversely, the arguments against precipitous change successfully arrested attempts for any meaningful change.

Here, it’s instructive to use Jason’s own example of CFCs and the ozone hole. While it’s true that the ozone hole was directly observable, and therefore it was easier to dismiss skeptics, it is also true that efforts to control CFC emissions began long before the hole in the ozone layer had been directly confirmed. Environmentalists in some countries successfully lobbied to have CFCs in aerosol cans eliminated more than a decade before the mid-1980s, when amounts of ozone were finally and decisively measured. The uncertainty of the risk, in other words, did not stand in the way of immediate — dare we say it, precipitous — public action.

Similarly, when the ozone hole was finally verified in 1985, it took all of two years for a global treaty to take shape controlling the use of CFCs. The goals set in Montreal, 1987: An immediate freeze in CFC emissions, and a 50% reduction in twelve years. Astonishingly, as the science surrounding ozone depletion became more alarming, the Montreal Protocol was strengthened further.

While climate change may be more difficult to observe, it’s a fallacy to say it’s less certain in it’s footing — the physics of infrared absorption and atmospheric chemistry have been understood, if imperfectly, since the time of Svante Arrhenius. That governments and industry have colluded to confuse this simple fact does not excuse them.

There’s a final point, unacknowledged in Jason’s original post, that climate change is only one symptom of our exponential growth in carbon emissions — the acidifcation of the world’s oceans being the most notable other. Similarly to climate change, short of massive reductions in CO2, our oceans face a long-term disaster of unimaginable proportions. (And this is quite separate from the problem of growing ocean temperatures, itself a grave concern.)

The point is that carbon emissions are not, by any standard, virtuous in and of themselves. Indeed, even outside of climate change, there’s good reason to believe they need to be eliminated.

Economic growth? Technological progress? Hell, fiscal sanity? Sign me up for all three. (Remember, vote November 7th!) But I cannot believe, given the balance of evidence today, that there’s much of a future for any of those three concepts without massive reductions in our CO2 emissions.