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From Tuesday's Daily Telegraph: New research suggesting that carbon dioxide affects the climate less than we believed gives us more time to reassess our strategy
Have we been granted a reprieve in the battle against global warming? If research by Alexander Otto and colleagues at Oxford University is to be believed, the climate is less sensitive to carbon emissions than we believed. Climate change is by no means over, but we may have more of a breathing space to do something about it.
The Intergovernmental Panel on Climate Change's previous best estimate put "climate sensitivity" at 3C; that is, for every doubling of carbon dioxide concentrations in the atmosphere, the mean global temperature would go up by three degrees centigrade. Otto's research suggests that figure is closer to 2C.
The news has been greeted with surprise and relief by climate scientists. Piers Forster, of the University of Leeds, told New Scientist this week that it's given him greater resolve. "If [previous estimates] were true, keeping the world below 2C [above pre-industrial temperatures, as the world's governments have pledged to do] would have been almost impossible... Now it looks like we have a chance." Previously, the environmental news had been dominated by CO2 concentrations in the atmosphere passing 400ppm.
The question that has arisen is: how should policymakers respond to the new information? Professor Julia Slingo, the Met Office's chief scientist, cautions that they must treat the new figures with caution. "We need to be very careful not to suggest that this downgrades the danger of climate change that we might face," she says.
But the new findings may add weight to the argument of those who argue that there are better responses than making grandiose pledges to cut emissions.
Most importantly, says Prof Bjørn Lomborg, the economist and author of The Skeptical Environmentalist, rich countries are better placed to deal with the problems of climate change than poor ones are, so encouraging economic growth is key.
"I'm surprised that people focus on helping Bangladesh avoid a couple of centimetres of sea level rise, instead of realising that if Bangladesh was as rich as Holland, they'd be much more able to deal with the effects of that rise," he says. And specific adaptations are important: "It drives me out of my skull when people say that Hurricane Katrina showed we need to cut greenhouse emissions. No, it showed you need to build better levees."
Prof Roger Pielke Jr, author of The Climate Fix, agrees: "We're always being reminded of our vulnerability to nature. It makes sense to adapt, especially in poor countries, which are the most vulnerable. It's also the most politically acceptable route, because it doesn't matter whether you think humanity is causing warming: it's simple prudence."
The extra heat trapped by greenhouse gases is not, as once imagined, simply warming the atmosphere: the story is more subtle and complex than that. The heat is still there, but in the short term we don't see it: it mostly warms the ocean. But eventually, the result will be the same: the extra heat will be released, but more slowly. This may be what is buying more time.
As interesting as the Otto paper is, it is still only one paper. "The most likely value of climate sensitivity hasn't changed much," says Slingo. "And we know that heat is being held in the oceans, so we know that faster warming will return." Pielke agrees. "No single paper fundamentally changes the landscape. We shouldn't be basing policies on a crystal ball telling us what the future holds, whether it's one degree or six."
We don't know what the long term holds. That doesn't mean the long term isn't important, says Lomborg, but it's important to find climate policies that do good regardless of exactly what the temperature is going to be in 2050. "For 20 years, the tone of the climate conversation has been panic. 'We're doomed, we gotta do something,' " says Lomborg. "But what we've done is expensive and does very little good."
He suggests investing in green technology innovation, which, he says, is much more cost-effective at reducing climate damage than carbon taxes. "If green energy continues to be more expensive than fossil fuels, we will never cut a lot," he says. "And we're not going to get the Chinese and the Indians on board. But if we can get technology to reduce the price of green energy below fossil fuels, everyone will want to buy it."
Lomborg points to the US, where controversial "fracking" for shale gas has reduced carbon emissions far more than green policies have in Europe, simply because the gas is cheaper and cleaner than coal, without it being in any way intended as a green technology.
Whatever the true figure for climate sensitivity is, our current approach is failing, he says. "Europe has been paying maybe $30-$40 billion a year on climate policies that aren't working. They make us feel good, but our children and grandchildren aren't going to care if we felt good. They're going to care whether we fixed the problem."
