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Climate Optimist Revisits Failures of His 'Wedges' Paper

Robert Socolow, the co-author of an influential plan to reduce carbon emissions, revisits his work seven years later to understand why it failed.
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Perhaps the most famous blueprint for slowing and reversing carbon emissions was the 2004 “wedges” paper by Princeton researchers Stephen Pacala and Robert Socolow. While the resulting project’s optimism, innovative approach — it includes a “Stabilization Wedges Game” and a musical lecture — and frequent citation have captured imaginations worldwide, policymakers continue to scuttle away from the hard choices it suggests for addressing climate change.

As Matt Jenkins described for in the April-May 2008 issue of Miller-McCune, (“A Really Inconvenient Truth”) "... Pacala and Socolow proposed assembling a package of greenhouse gas reduction measures, or 'stabilization wedges.' Each wedge can ultimately replace 1 billion tons — or one gigaton — of carbon emissions per year. The two researchers proposed 15 possible wedges and suggested that seven would be needed ..."

Last week, Socolow revisited his paper in an article for the Bulletin of the Atomic Scientists. While he’s disappointed that the rate of carbon emission continues to climb and the resistance to plans for reductions is strong (but not monolithic, as California’s air regulators showed), he stands behind the science and the goal of the project: a flat carbon emissions rate in 50 years, then reaching a rate of nearly zero emissions in the next 50 years. (The plan uses rates instead of absolute numbers because the authors recognize growing world populations will generate more greenhouse gases.)

But the passage of time and global inaction has made that task harder. The mitigation goal that once required seven "wedges" now requires nine, he wrote.

BY THE WAYWhen news breaks, this blog shows that Miller-McCune has the topic covered.

When news breaks, this blog shows that Miller-McCune has the topic covered.

The mechanical and aerospace engineer had some idea on how his and Pacala’s call to action could have better crafted.

“Over the past seven years,” he wrote, “I wish we had been more forthcoming with three messages: We should have conceded, prominently, that the news about climate change is unwelcome, that today's climate science is incomplete, and that every ‘solution’ carries risk. I don't know for sure that such candor would have produced a less polarized public discourse. But I bet it would have. Our audiences would have been reassured that we and they are on the same team — that we are not holding anything back and have the same hopes and fears.

“It is not too late to bring these messages forward.”

What requires more research, he says, are social science insights into "inconvenient truths," and studies on how to balance the stabilization strategies with the upheaval they will cause to the status quo. The analogy of "braking" — whether you slam or ease on the brake pedal — gives a sense of the range of actions available. Rapid action on biofuels or nuclear power would likely have more negative consequences than would rapid action for wind or solar power.

Their formulation has been an influential tool for thinking about how to solve the climate crisis — not through one magic solution but through a combination of several. Most importantly, their plan aimed to show that climate action was something possible through existing energy technologies.

As the abstract begins, "Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem for the next half-century." The answer was not mysterious. It only required the willingness to act.

But largely, Socolow says, the paper's "core messages ... have not led to action."

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