I managed to find a post I wrote for this site on December 31, 2010, titled “Some perspective on the 2C limit for the new year”. I’ve pasted it below, in its original form. (Note that since I wrote this nearly five years ago, another IPCC report has been published.)
Imagine, if you will, a report on the environment commissioned by the United Nations that required the work of a 152-member committee from 58 countries.
And consider that the final report included the following text:
Clearly man has had nothing to do with these vast climatic changes [moving in and out of ice ages] in the past. And from the scale of the energy systems involved, it would seem rational to suppose that he is not likely to affect them in the future. But here we encounter another fact about our planetary life: the fragility of the balances through which the natural world that we know survives. In the field of climate, the sun’s radiations, the earth’s emissions, the universal influence of the oceans, and the impact of the ice are unquestionably vast and beyond any direct influence on the part of man. But the balance between incoming and outgoing radiation, the interplay of forces which preserves the average global level of temperature appear to be so even, so precise, that only the slightest shift in the energy balance could disrupt the whole system. It takes only the smallest movement at its fulcrum to swing a seesaw out of the horizontal. It may require only a very small percentage of change in the planet’s balance of energy to modify average temperatures by 2°C. Downward, this is another ice age; upward, a return to an ice-free age. In either case, the effects are global and catastrophic.
By now, those of you used to what passes for my sense of humor are no doubt wondering which of the earliest IPCC reports I”m talking about and quoting. Was it the Second Assessment Report, published in 1995? The First, from 1990? (The most recent one, published in 2007 and commonly known simply as “the IPCC report”, was the Fourth.)
Of course not. The document in question is the book, Only One Earth: The Care and Maintenance of a Small Planet, by Barbara Ward and Rene Dubos, published in 1972. Yes, 1972. With that knowledge in hand, please take a minute to re-read the paragraph I quoted.
While I haven’t read the whole book, what I’ve found from quickly skimming it suggests that much of it is as thought provoking, and sometimes as jarring, as the text above.
You can reach your own conclusions about this remarkable book which seems to have fallen through the cracks of our collective memory. For me, the “here’s yet more proof that we knew what we were doing to the environment long before even James Hansen’s 1988 Congressional testimony” factor is more than enough to ponder.
Happy New Year, one and all. Be safe, hug your loved ones, and find perspective wherever you can. 2011 beckons, and it”s going to be a lot of things, but “dull” isn’t on the list.
In case you’re wondering, I found this book while trying to track down the source of the largely unquestioned 2°C-of-warming guardrail that supposedly separates “acceptable” from “unacceptable” climate impacts. Somewhere in the vast and dusty hallways of the Intertubes I stumbled over a reference to the book, and, much to my delight, a used book dealer had a copy for sale on Amazon at a stupid-cheap price.
This is the earliest discussion I could find of 2°C being used in any way similar to the “guardrail”, and it only strengthens my belief that we’ve grandfathered in this guideline and would come up with a lower number if we started from scratch with our current understanding of the Earth System.