What Will It Take to Solve Climate Chang

January 22 [Tue], 2013, 6:29
Australia had to add athis week. Meteorologists used royal purple to denote an off-the-charts high temperature of 50 degrees Celsius (122 degrees Fahrenheit), part of an unprecedented heat wave and ongoing wildfires occurring down under this month. On the other side of the globe,on record in the contiguous U.S., surpassing the previous record-holder by a full degree F (0.6 deg C). In short, global warming is continuing to turn up the heat--so what are we going to do about it?

The goal is simple: reduce greenhouse gas emissions to restrainor even begin toconcentrations in the atmosphere. But the challenge of achieving that goal is large--greenhouse gas emissions are intimately related to , which is the motor of the global economy.

One idea to begin to solve this problem, mooted in 2004 by Princeton University mechanical engineer Robert Socolow and ecologist Stephen Pacala, was to identify what the scientists dubbed ""--one billion metric ton reductions in carbon emissions that could be maintained for the next 50 years. So, for example, stopping any further increase in greenhouse gas emissions could be done by employing several of these wedges, such asor replacing coal-fired power plants withones.

Employ enough of these wedges--seven in the estimation of Socolow and Pacala--and thebegins to dissipate. And the researchers offered 15 potential wedges--ranging fromto ending deforestation--to achieve the goal. As the co-authors put it in thepublished in Science: "Humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem."

Great! The only problem is: if we do indeed possess the know-how, we have yet to employ it. Eight years later, global greenhouse gasfaster than ever. We have lost time, and that time will cost us, both in terms of the cost of combating climate change and the ultimate impacts.

According to apublished online in Environmental Research Letters on January 9, the world now likely needs 12 wedges just to get back to the business-as-usual scenario outlined by Socolow and Pacala in 2004. Add another nine billion ton wedges if you want to stabilize emissions at last year's levels, and add another 10 if you'd like to keep greenhouse gas concentrations from rising above 500 parts-per-million. Already, concentrations are at 394 ppm, up from 280 ppm before the dawn of widespread fossil fuel burning. That's if you also want the global economy to continue to grow at the same time.

Such global growth may be vital as societiesto the 2 billion or so people still reliant on wood, dung and kerosene for their cooking and lighting needs. Even more challenging, the key to reducing emissions is , or at least the impacts of that burning--and all the technologies needed to do that are(CCS),(nuclear) or(renewables). The world will need to deploy "tens of terawatts of carbon-free energy in the next few decades," as the researchers write in .

What such a "" would mean specifically remains entirely undiscussed in the analysis, as Socolow notes in a written critique of the paper shared this week with journalists. Regardless, that kind ofcertainly seems challenging, which is why some have begun to wonder whether it's time to at least explore technologies that might reduce the worst of global warming, collectively known as , such aswith iron or . Of course, such solutions present their own challenges like: who controls the planetary thermostat? "The stricter the [climate] goal, the greater the risk of recklessness," such as ill-considered geoengineering schemes, warns Socolow.

Or, as earth system scientist Steven Davis of the University of California, Irvine, and lead author of the wedges reanalysis argues: "The only real solution to climate change is to stop dumping CO2 into the atmosphere altogether." If we want to begin to restrain global warming, we better get started--and soon.

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