The precise effects of climate change aren't certain -- and don't need to be. Photographer: Yevgen Timashov via Getty Images
The precise effects of climate change aren't certain -- and don't need to be. Photographer: Yevgen Timashov via Getty Images

The world's failure to take meaningful action on climate change may one day be seen as the gravest mistake of our time. How to account for this failure?

There are many reasons for it -- but principally lack of leadership. Governments won't succeed in this endeavor until they start risking political capital on the cause and, equally important, rethink their arguments. Climate change is neither an inevitable cataclysm nor a scientific hoax, the twin poles that have defined this debate. It is a relatively straightforward but profound risk against which the world must insure itself.

QuickTake Climate Change

The Intergovernmental Panel on Climate Change has just published the third of three working-group reports on where the science of climate change stands, on the effects that the world can expect if greenhouse-gas emissions aren't curbed, and on the options for reducing those risks. Later this year it will issue a grand Synthesis Report gathering all these pieces together.

These thousands of pages add to the tens of thousands already published in previous IPCC exercises, and the message is essentially the same: The world needs to act. For all that, and despite the ambitions of the Kyoto Protocol adopted in 1997, global greenhouse-gas emissions continue to grow.

This is in part because the world's dependence on fossil fuels isn't easy to dislodge -- not quickly, at any rate, and certainly not without cost. The economic burden of prompt mitigation happens here and now; the main economic benefits are decades away (other benefits, such as cleaner air, will come sooner). That's a tough case to make in a democracy.

So be it. Politicians in the U.S., Europe and the rest of the world have largely ducked the responsibility, too often preferring grandiose speeches and hollow international initiatives to cost-effective policies that stand a chance of working -- such as putting a tax on carbon.

It's too easy for politicians to blame popular resistance to such measures on voters' shortsightedness and ignorance of the proven science. Governments and their advisers have fallen into the habit of overstating their certainty about the consequences of inaction and needlessly narrowing the range of appropriate responses. It's as though they've decided that people need to be scared into accepting whatever governments might propose, rather than guided to weigh intelligent choices.

It's clear that human behavior is changing the climate, but just how quickly, and with what exact consequences, is harder to say. The precise effects on weather, sea levels, incidence of disease and drought, species diversity, ocean acidification and so forth -- none of this is known with certainty.

The point is, it doesn’t need to be. Policies to mitigate climate change are best viewed as insurance against great but imperfectly understood risks. Every voter understands the concept of insurance.

And insurance companies typically don’t try to frighten people into buying their products. Instead, they present it as a sensible, even boring, necessity. Scare tactics about climate change have not only failed to move public opinion, but they've also undermined trust in government, which was too low to begin with.

Another worthwhile tactical shift would be to acknowledge that the remedies aren't clear-cut. Offering voters a choice between acting "quickly and dramatically" or facing "catastrophic" harm, as U.S. Secretary of State John Kerry did recently, doesn't help. The costs of mitigation vary enormously, as does who would bear the burden. Addressing these complications requires more debate, not less.

The advantage of a carbon tax is that it offers a market-based approach to setting priorities. But the broader point is that taking climate change seriously doesn't mandate any and every proposal for reducing emissions. Some are too expensive to make sense (retrofitting old machines and buildings, for instance, can cost much more than making new ones energy-efficient), and there's no shame in saying so. Other ideas are too promising to ignore (nuclear power, carbon-capture technologies, geoengineering), and there's no shame in saying that, either. Adapting to higher temperatures, as well as trying to limit the increase, should also be part of the discussion -- an idea that the IPCC is belatedly coming around to.

As in every enterprise requiring international cooperation, U.S. leadership is indispensable. Unfortunately, the issue of climate change has been drawn into the maw of the country's bitterly partisan politics. This, too, is a failure of leadership.

In the U.S. and around the world, prominent politicians of every stripe should make clear that the debate over climate change need not demand the unconditional surrender of competing worldviews. It is simply a discussion about the practical and economical steps necessary to manage risk.

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