On our current emissions path, projected warming is catastrophic even in the unlikely event of a low climate sensitivity of 1.5 – 2.0°C. From Michael Schlesinger et al 2012.
Here’s The Economist’s idea of responsible journalism. Begin by quoting UN chief climate negotiator Yvo de Boer on the forthcoming fifth assessment by the Intergovernmental Panel on Climate Change (IPCC):
THAT report is going to scare the wits out of everyone.
Then dig up some unpublished, unsubstantiated chart to make the case “it might be less terrifying than it could have been.” No, seriously, the Economist devoted an entire article to argue that a draft climate change report “might be less terrifying than it could have been.”
I guess if The Economist had been leaked the draft medical report from a decade ago that Steve Jobs had a neuroendocrine tumor of the pancreas (rather than a carcinoma), they would have written an entire piece explaining his condition “might be less terrifying than it could have been.”
One of the country’s leading climatologists, Michael Mann, emailed me:
Among other things, the author hopelessly confuses transient warming (the warming observed at any particularly time) with committed warming (the total warming that you’ve committed to, which includes warming in the pipeline due to historical carbon emissions). even in the best case scenario, business as usual fossil fuel burning will almost certainly commit us to more than 2C (3.6 F) warming, an amount of warming that scientists who study climate change impacts tell us will lead to truly dangerous and potentially irreversible climate change. the article does a disservice to Economist readers by obscuring this critical fact. Sadly, it is hardly the first time in recent history that the Economist has published flawed and misleading stories about climate change.
Mann is referring in part to the widely debunked Economist piece from earlier this year on climate sensitivity. Another key mistake The Economist keeps making is confusing climate sensitivity with projected future warming. I discussed the crucial differences here.
The good news is that The Economist article might be less dreadful than it could have been. For instance, I didn’t find any typos.
Here’s the chart in question:
The Economist seems blissfully unaware that while the Thawing Permafrost Could Cause 2.5 Times the Warming of Deforestation (!) and add up to 1.5°F to warming in 2100 by itself, “Participating modeling teams have completed their climate projections in support of the [IPCC’s] Fifth Assessment Report, but these projections do not include the permafrost carbon feedback.”
The Economist also seems blissfully unaware of the fact that we are currently close to the 1000 ppm emissions pathway. And The Economist also seems blissfully unaware that stabilizing anywhere near 450 ppm atmospheric concentration of CO2 would require immediate and sustained action to replace the world’s fossil fuel system with one based on carbon-free energy — precisely the kind of aggressive action this piece seems designed to undercut.
But The Economist is actually aware that the chart it published is probably not terribly germane:
There are several caveats. The table comes from a draft version of the report, and could thus change. It was put together by the IPCC working group on mitigating climate change, rather than the group looking at physical sciences. It derives from a relatively simple model of the climate, rather than the big complex ones usually used by the IPCC. And the literature to back it up has not yet been published.
Translation: This chart is most likely BS, but it is the best we could find to justify our lame contrarianism.
As climatologist Kevin Trenberth emailed me:
The Working Group III IPCC report [on mitigation] is no where near final, the final draft has not even been produced yet. Moreover WG III is not responsible for making any statements about climate sensitivity and have no business doing so. The IPCC parallel process hinders exchanges among WGs and the WG I results [on the physical science basis]may not be available to WG III, but will be in due course as there is some staggering of the reports. In the meantime, the Economist report is irresponsible.
For the record, the equilibrium climate sensitivity is how much warming you get if the world suddenly adopts a super-aggressive effort to cut carbon pollution and CO2 levels rise no further than 560 ppm (double preindustrial levels) — and there are no major “slow” feedbacks (like the permafrost defrosting). The ECS is a far less interesting and consequential subject than the fact that we are headed way, way past 560 ppm or that the real-world slow feedbacks are expected to make a very big contribution to warming this century.
Why does The Economist keep writing contrived pieces on sensitivity rather than telling the real story of manmade climate change? One as yet unrefuted theory is that they like puns more than they like the truth. Their March piece was headlined “A sensitive matter” and their new piece is headlined “Sensitive information.” Perhaps their next one will be titled “Nonsensitivity.”