Shall we mitigate or adapt?


‘Both,’ CU experts say

Polluting less is a good idea. But in the context of climate, experts say, emitting less carbon is not enough.

Mitigation, or cutting carbon emissions, can’t supplant adaptation, they contend. Adaptation can mean moving people away from low-lying coastal areas. It can even include radical “geo-engineering” initiatives, such as spewing massive volumes of light-reflecting particles into the high atmosphere.

The magnitude of the problem, they say, calls for both strategies.

Carl Koval

Carl Koval

Carl Koval, a professor of chemistry and biochemistry and director of the University of Colorado’s Energy Initiative, outlined the mitigation challenge recently.

By mid-century, global energy demand might double. Electricity demand might triple. Most of that energy will come from burning fossil fuels, he noted. And much of the world’s electricity is expected to be generated by coal, the dirtiest fossil fuel.

If such growth is fueled by black gold, atmospheric CO2 will keep soaring, and climate changes could be dramatic. The world should deploy massive sources of carbon-free energy, experts say.

In 2005, the world consumed about 15.7 terawatts of electricity. By 2050, worldwide demand could be 10 to 20 terawatts more.

Koval noted the “stabilization triangle” strategy proposed in 2004 by scholars at Princeton University.

The approach divides CO2-reduction strategies into discrete “wedges.” Each wedge would cut CO2 emissions by 100 gigatons over 50 years. By the end of five decades, each “wedge” would be cutting four gigatons of CO2 emissions annually.

Each wedge is technically possible. Each relies on strategies proved on smaller scales.

The more wedges, the greater the benefits. As Koval noted, one wedge could be achieved by generating electricity at 60-percent efficiency. Today’s average is 35 percent. Building wind turbines on 3 percent of the United States’ surface would make another wedge.

Stephen Pacala and Robert Socolow at Princeton University have argued that the world can stabilize carbon emissions with specific strategies that employ current technology. Each strategy would compose a “wedge” of carbon-emissions reduction, each representing a gigaton of reduced carbon or 4 gigatons of reduced CO2. Though Pacala and Socolow suggest that eight wedges could stabilize emissions, CU Professor Roger Pielke Jr. and others contend that the technological demands are much greater, and that perhaps twice as many wedges will be needed.

Stephen Pacala and Robert Socolow at Princeton University have argued that the world can stabilize carbon emissions with specific strategies that employ current technology. Each strategy would compose a “wedge” of carbon-emissions reduction, each representing a gigaton of reduced carbon or 4 gigatons of reduced CO2. Though Pacala and Socolow suggest that eight wedges could stabilize emissions, CU Professor Roger Pielke Jr. and others contend that the technological demands are much greater, and that perhaps twice as many wedges will be needed.

One wedge could be attained by expanding the use of solar panels by 700 times. Another could come from building 500 new nuclear-power plants. Yet another could involve “sequestering,” or burying, 3.5 gigatons of carbon dioxide underground every year.

It would probably take all of those wedges plus others just to stop the growth of C02 emissions, experts say. Energy demand and population growth are accelerating. Stopping the growth of emissions is a huge challenge. Making steep cuts would be even harder.

Significant mitigation poses political challenges, not just technical obstacles, experts say. Reducing emissions yields benefits only over the long term, and policy-makers tend to focus on immediate concerns. For that reason and others, they contend, mitigation should not supplant adaptation.

Roger Pielke, Jr.

Roger Pielke, Jr.

Roger Pielke Jr., a CU professor of environmental studies, often emphasizes those points.

Writing in the University of Pennsylvania Law Review in 2006, Pielke argued for a “sustainable” climate policy, one in which costs and benefits are “temporally balanced.”

“Even if society takes immediate and drastic action on emissions, there can be no scientifically valid argument that such actions will lead to a perceptibly better climate in our lifetime,” Pielke wrote.

Pielke does not suggest that “we throw up our hands and do nothing to mitigate the effects of climate change.” Rather, he notes, the only policies that can effectively ameliorate the climate change during our lifetimes “will be adaptive.”

In a July interview with The New York Times, Pielke reiterated this point. He noted that people may be confused by press coverage of the stream of scientific studies, some of which might be seen as rebutting previous studies. People should embrace policies that make sense regardless of the uncertainties of climate projections, he said.

“The example of reducing losses to hurricanes is a good one, where the actions that make the most sense are really independent of the debate over greenhouse gases and hurricane behavior,” Pielke said. Policies that make the most sense in the short term, he suggests, are adaptive.

And in the journal Nature this spring, Pielke and other scholars argued that the challenge of stabilizing and reducing global emissions is greater than many believe. Pielke, Tom Wigley of the National Center for Atmospheric Research in Boulder, and Christopher Green of McGill University contend that the Intergovernmental Panel on Climate Change presumes that much mitigation will stem from “spontaneous decarbonization.”

“The IPCC implicitly assumes that the bulk of the challenge of reducing future emissions will occur in the absence of climate policies,” they write.

Energy use and carbon emissions are already greater than IPCC scenarios predicted. Given the rapid development in China and India, they write, “it is likely that we have only just begun to experience the surge in global energy use associated with ongoing rapid development.”

“There is no question about whether technological innovation is necessary — it is,” they conclude. “The question is, to what degree should policy focus directly on motivating such innovation?”

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