A few days ago, Matt Ridley had a piece in the Wall Street Journal, Cooling Down the Fears of Climate Change, in which he writes:
... In short: We can now estimate, based on observations, how sensitive the temperature is to carbon dioxide. We do not need to rely heavily on unproven models. Comparing the trend in global temperature over the past 100-150 years with the change in "radiative forcing" (heating or cooling power) from carbon dioxide, aerosols and other sources, minus ocean heat uptake, can now give a good estimate of climate sensitivity.
The conclusion—taking the best observational estimates of the change in decadal-average global temperature between 1871-80 and 2002-11, and of the corresponding changes in forcing and ocean heat uptake—is this: A doubling of CO2 will lead to a warming of 1.6°-1.7°C (2.9°-3.1°F).
This is much lower than the IPCC's current best estimate, 3°C (5.4°F).
Mr. Lewis is an expert reviewer of the recently leaked draft of the IPCC's WG1 Scientific Report. The IPCC forbids him to quote from it, but he is privy to all the observational best estimates and uncertainty ranges the draft report gives. What he has told me is dynamite.
Tim Worstall at Forbes writes in Maybe Climate Change Just Really Isn't A Problem After All?
... That is an extraordinary claim and clearly requires extraordinary evidence to support it. Much as I like Ridley (we swap stories and information regularly) I’m not going to accept it on the basis of one newspaper column. And Ridley wouldn’t expect me or you to either.
But if it is true then climate change stops being a looming diaster threatening all we hold dear and becomes instead just a minor background effect. One that we really don’t have to do anything particularly active about at all: the advancing technologies of low or non-carbon energy generation will take care of it all for us. ...
I share Worstall's caution but I also think that to acknowledge that the earth is warming and humans play a contributing role, something for which there seems to be strong agreement, doesn't tell you the magnitude of the impact or what policy options are optimal. As I've pointed out in early posts, the global average temperature has plateaued for more than a decade. Violent hurricane activity has not increased. Arctic ice is melting, although, as I understand it, it is summer ice not winter ice where the change is being observed. Dueling scientists publish studies with partisans cherry-picking the elements that are most supportive of their narrative. I do not doubt that human behavior is having impact on the climate. But I am uncertain of how robust climate models are and how serious the challenges are likely to be.
One thing I do like is the following quote from Bryan Walsh, senior editor at Time. I take issues with some aspects of his article, Anthropocene: Do We Need a New Environmentalism for a New Age?, but I did like this.
... But Kloor isn’t really talking about politics. Rather, I think, it’s how we conceive of the environment and environmentalism. The message of the modernist greens is: in a world of 7 billion plus people, all of whom want (and deserve) to live modern, consuming lives, we need to be pragmatic about how we use—and how much we protect—nature. We don’t have any other choice, so we’d better start dealing with the realities on the ground.
The realist in me thinks the modernist greens are right. There are simply too many of us, and we want too much, for our footprint on the Earth to get anything but bigger. And I’m cheered by the scientists and thinkers who suggest that we might be able to have it all—a huge, thriving human population, and an environment that can support it—as long as we plan right. What’s more, I’m very conscious that industrialization and globalization have largely been forces for good, expanding human access to wealth, health and longevity. There’s no better time in history to be human being. Industrialization is not going to be rolled back—and it shouldn’t be.
There’s also a larger social shift at work that’s altering our concept of nature. Today more human beings live in cities than live in the countryside, and that proportion will only grow in the future: by 2050, as many as three-quarters of the estimated 10 billion people on Earth will live in urban areas. This is a historic change—as recently as 1800 just 2% of the world’s population lived in cities—and it’s a sign that humanity, inevitably, is decoupling from nature. I suspect that’s true even of environmentalists, who are just as likely as anyone else to come into contact with what passes for wilderness these days more in a managed park than untrammeled rainforest or woodland. For a lot of us, “environmental issues” increasingly have to do with improving urban life—think cleaner mass transit or access to organic food in farmer’s markets. As the writer Emma Marris argued in her book Rambunctious Garden, environmentalism needs to stop drawing simplistic lines between what’s natural and what’s manmade—with the former always good and the latter always bad—and learn to celebrate the biodiversity that’s in our backyards. ...