In 2004, Robert Socolow and Stephen Pacala published an article in Science, (subscription needed) introducing the wedge: over 50 years, the savings from currently available technology could be ramped up to save 1 billion metric tons of greenhouse gases in the last year, saving in total 25 billion metric tonnes of carbon-equivalent (or 92 metric tonnes of carbon dioxide equivalent). Using optimistic assumptions about the rate of GHG growth, they calculated that 7 wedges could stabilize GHG by 2055. Of course, more sources of GHG reduction were needed to reduce GHG emissions.
The authors emphasize paying attention to the big numbers first, the technologies that could lead to 1 billion metric tonnes of reduction in year 50.
The disadvantages in the wedge concept were in how their ideas were received. One was the appeal to so many of solving climate change with only 7 wedges (with perhaps some more to bring reductions down), the appeal of solving climate change with existing technologies, the appeal of getting to choose which solutions we want over the expert community’s more prosaic hopes that there would be enough solutions.
As of the September 10, 2010 Science, Farewell to Fossil Fuels? (subscription required), the estimate is now 25. Socolow and Pacala never said 7 wedges were enough, but the small number did make finding solutions look easier.
Socolow and Pacala encouraged this with the Stabilization Game, giving all of us a chance to vote for what we want, and vote against what we don’t want. Eventually, I rejected the wedge concept as a teaching tool because it was being abused by so many for all those reasons.
Update: It was not an interview. Socolow has posted comments, including more optimistic assumptions than I see elsewhere on the number of wedges needed.
Robert Socolow has reached the same conclusion. In a National Geographic
interviewsummary of a Socolow talk, he now says the wedge concept was a mistake:
“With some help from wedges, the world decided that dealing with global warming wasn’t impossible, so it must be easy,” Socolow says. “There was a whole lot of simplification, that this is no big deal.” …[I]nstead of providing motivation, the wedges theory let people relax in the face of enormous challenges, he now says.
“The job went from impossible to easy” in part because of the wedges theory. “I was part of that.”
And from there, he says, a disturbing portion of the population moved to doubt that the problem is even real…
“The intensity of belief that renewables and conservation would do the job approached religious,” Socolow said. But the minimum goals “are not enough,” he said, and “the fossil fuel industry will not be pushed over.”
Who was most likely to abuse the web concept?
Henry Lee, who directs the environment program at the Harvard Kennedy School’s Belfer Center for Science and International Affairs, said many people were optimistic that, by now, the world would be making considerable progress on climate.
“I think we were victimized more by the advocacy community than by science,” Lee said. Using Socolow’s wedges theory and similar arguments, advocates suggested “you could get all of this and pay nothing. I think people feel angry now, that it’s going to cost them.”
Lee agreed Socolow’s ideas were misused, or at least misread. “If you look at the wedges they weren’t a little. There was nothing in the Socolow plan that says this is a slam-dunk and easy to do.”
“The wedge theory still is valuable,” Lee added. “The price tag may be higher, but I think he made an important contribution. If you’re going to do something about climate change, there is not one silver bullet. That’s the point he made at the time, and it’s still valid.”
Hopefully, we can still use some of what they taught (focus on the large, the solutions are silver buckshot). Hopefully we can find ways to help the advocacy community understand that we don’t have so many solutions that we can reject any.