It’s not about saving the planet

It is an iron law of politics that no discussion of global warming can take place in the absence of the apocalypse. Or rather, two apocalypses. Among believers in the global warming thesis, the apocalypse consists in the variety of biblical disasters to be visited upon us by a vengeful God if we do nothing. Among the skeptics, the apocalypse takes a more prosaic, though no less awful form, namely the destruction of our economy, our way of life, and our system of government, unless we do nothing.

I do not think I am exaggerating. A Leger poll earlier this year found one in five Canadians now believe global warming “will destroy the Earth.” The Conservative government’s recent Clean Air Plan, the Toronto Star editorialized, with its unhurried approach to the problem, “could spell disaster for the world as we know it today.”

On the other side, global warming skeptics warn that the entire thesis is nothing more than a plot to destroy the economies of the West, a Trojan horse for the imposition of a global anti-capitalist order. My colleague Terry Corcoran, from his aerie high atop the Financial Post editorial page, sees the advent of a “new green totalitarianism,” the “green police state,” and other green ills. When the previous Liberal government unveiled its next-to-last climate change plan, the Alberta government claimed it would sound “the death knell for the Canadian economy.”

We would appear, as Woody Allen said, to stand at a crossroads, one path leading “to despair and utter hopelessness,” the other to “total extinction.” (“Let us pray that we have the wisdom to choose correctly.”)

So it is a delight to be able to tell both sides that they can calm down. I do so not on my own account, but on a reading of the report to the British government on The Economics of Climate Change by the economist Sir Nicholas Stern, otherwise known as the Stern Review. Yet despite the headline figures it provoked -- Seven Trillion Dollars! -- the review’s signal contribution may be to encourage both sides to adopt a more measured tone. We have a serious problem on our hands, if you believe the science. But it is an eminently manageable one, if you believe Sir Nicholas.

To be sure, his report does not stint on the plagues of locusts. Droughts, floods, famine, disease, it’s all there, at least in the worst-case scenario. But when it comes to totting up the economic costs associated with these misfortunes, the numbers are surprisingly small. A two to three degree warming of the planet over the next several decades, he calculates, would cost the global economy between 0 and 3 per cent of GDP annually. A more severe warming, in the range of five degrees, would up the ante to between 5 and 10 per cent of GDP.

Only with the help of the very worst of worst-case assumptions, and some statistical jiggery-pokery -- adjusting for the disproportionate impact on the developing world, for instance -- do we get to the 20 per cent reduction in world living standards that so excited the headline writers. Sir Nicholas himself prefers “at least 5 per cent” as a shorthand estimate, which is painful enough, but hardly earth-destroying. And bear in mind that this is not 5 per cent subtracted from current levels, or a 5 per cent decline all in one year, but 5 per cent over the next two centuries.

So much for apocalypse one. What about apocalypse two: the cost of averting, or at least mitigating (some degree of warming is inevitable no matter what we do) this scenario? How much the Earth warms will depend on the level at which the total concentrations of greenhouse gases in the atmosphere, now at 430 parts per million and growing, reach their peak. Sir Nicholas calculates that holding these to 550 parts per million or less by the year 2050 would be sufficient to give some assurance that the atmosphere will not heat up by more than a couple of degrees.

What would that mean, in terms of annual emissions? Again, there are a range of possibilities, but the report sketches a path whereby emissions top out in the next 10 to 20 years, then fall by about 1 to 3 per cent per year after that, or a total reduction of 25 per cent by 2050. That is in fact rather less than the 45 to 65 per cent reduction envisaged in the Conservative plan.

And the cost? Here it is the skeptics’ turn to be confounded. Sir Nicholas estimates that, with the help of such market-friendly instruments as tradeable emissions credits and carbon taxes, the task could be accomplished for a total cost of just 1 per cent of GDP. A five to one payout: no matter how you figure it, that’s a pretty good investment.