Climate Change Waits For No Oneby Bill Chameides | October 26th, 2011
posted by Wendy Graber (Researcher)
Pacala and Socolow’s (2004) stabilization wedges focused on ways to reduce emissions from a business-as-usual scenario in which CO2 concentrations reached 850 ppm by mid-century to one that stabilized global concentrations at 550 ppm. Back in 2004 Pacala and Socolow needed 7 of 15 wedges to stabilize emissions. Stabilizing emissions at today's levels would require more wedges. Figure is from EPA and was reproduced from Pacala and Socolow (2004).
Too costly to cut emissions or too costly to wait?
Two very different views of the climate-carbon conundrum have appeared in print of late: one from the Wall Street Journal and the other from Rob Socolow, climate scientist of Princeton University.
The WSJ View
In the Wall Street Journal an editorial, entitled “The Post-Global Warming World,” posits the following: “The question is whether it makes sense to combat a potential climate threat by imposing economically destructive regulations and sinking billions into failure-prone technologies that have their own environmental costs.” If you are “wearier” and “wiser,” the folks at the Wall Street Journal imply, you will definitely answer their question in the negative. Well, I’m not sure about the weary part, but I definitely want to be counted among the wiser; nevertheless, I refuse to answer the question on the grounds that I don’t accept the premise.
So would Rob Socolow, I think. He painted a very different picture in an article entitled “Wedges reaffirmed” published in late September in the Bulletin of the Atomic Scientists. Socolow along with Princeton colleague Steve Pacala got heads turned in the climate change world when they published their seminal paper on so-called stabilization wedges in Science in 2004. In the paper they made the case that even using today’s (i.e., from 2004) technologies carbon emissions could slowly but surely be lowered over the first half of the 21st century. And lowered to such an extent that we would be in a position to achieve long-term stabilization of atmospheric carbon dioxide (CO2) concentrations at or below a doubling of its pre-industrial value.
Current Technologies Can Stabilize Emissions
Unlike many of the other solutions being bandied about back then, their scenario did not rely on one single technology, but a portfolio of technologies. That is to say they embraced a “silver buckshot” approach rather than a silver bullet one. They estimated that a stabilization pathway could be attained by adopting seven of 15 low-carbon technologies (with efficiency counted as a “technology”).
Each of these technologies was depicted in their paper as a “wedge” such that a combination of seven kept carbon dioxide emission flat over the ensuing 50 years. They did not argue that it would be easy, but that it was possible. In Socolow’s own words: “I like to say we decomposed a heroic challenge into a limited set of monumental tasks.”
The climate science world took note of the wedges concept and iterated on it endlessly.* The world, however, did little in the way of implementation.
The Cost of Inaction
Now in 2011, Socolow revisits the wedges argument. The cost of our seven-year procrastination is striking. In the seven years since then global greenhouse emissions have increased by about twenty five percent.** Keeping emissions at today’s level compared to 2004’s level would, Socolow estimates, add an additional 50 ppm of CO2 to the equilibrium concentration (the current concentration is about 390 ppm) and about 0.75 degrees Fahrenheit to the average global surface temperature. And that’s not all. Unfortunately, stabilizing CO2 concentrations at today’s levels will now require nine wedges instead of seven. In short a daunting challenge has become even more daunting and we are stuck with higher temperatures and more CO2 in the atmosphere. But, in Socolow’s view, still the path to follow. And so, even though the risks of climate change are imperfectly defined — in Wall Street Journal jargon they pose a “potential” threat, Socolow counts himself among the “advocates for prompt action.”
There is, I believe, a rhetorical question in Socolow’s piece, although it is never explicitly asked: How much longer can we afford to wait?
** The seven year interval refers to 2001 to 2008 as there is a lag in producing the global dataset. Pacala and Socolow based their 2004 paper on emissions data from 2001. Today’s emissions refer to 2008 — the latest year with global data. Note: 2011 emissions may be lower due to the effects of the recession.filed under: climate change, faculty, global warming
and: Rob Socolow, stabilization wedges, Steve Pacala, Wall Street Journal, wedges