[LINK] "What It Would Really Take to Reverse Climate Change"

[rfmcdonald]

At IEEE Spectrum, Ross Koningstein and David Fork argue from a failed Google project that green energy won't be enough to prevent a climate meltdown, that new technologies--geoengineering--will be needed to prevent atmospheric carbon dioxide from causing catastrophe.

We had some useful data at our disposal. That same year, Google had completed a study on the impact of clean energy innovation, using the consulting firm McKinsey & Co.’s low-carbon economics tool. Our study’s best-case scenario modeled our most optimistic assumptions about cost reductions in solar power, wind power, energy storage, and electric vehicles. In this scenario, the United States would cut greenhouse gas emissions dramatically: Emissions could be 55 percent below the business-as-usual projection for 2050.

While a large emissions cut sure sounded good, this scenario still showed substantial use of natural gas in the electricity sector. That’s because today’s renewable energy sources are limited by suitable geography and their own intermittent power production. Wind farms, for example, make economic sense only in parts of the country with strong and steady winds. The study also showed continued fossil fuel use in transportation, agriculture, and construction. Even if our best-case scenario were achievable, we wondered: Would it really be a climate victory?

A 2008 paper by James Hansen [PDF], former director of NASA’s Goddard Institute for Space Studies and one of the world’s foremost experts on climate change, showed the true gravity of the situation. In it, Hansen set out to determine what level of atmospheric CO2 society should aim for “if humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted.” His climate models showed that exceeding 350 parts per million CO2 in the atmosphere would likely have catastrophic effects. We’ve already blown past that limit. Right now, environmental monitoring shows concentrations around 400 ppm. That’s particularly problematic because CO2 remains in the atmosphere for more than a century; even if we shut down every fossil-fueled power plant today, existing CO2 will continue to warm the planet.

We decided to combine our energy innovation study’s best-case scenario results with Hansen’s climate model to see whether a 55 percent emission cut by 2050 would bring the world back below that 350-ppm threshold. Our calculations revealed otherwise. Even if every renewable energy technology advanced as quickly as imagined and they were all applied globally, atmospheric CO2 levels wouldn’t just remain above 350 ppm; they would continue to rise exponentially due to continued fossil fuel use. So our best-case scenario, which was based on our most optimistic forecasts for renewable energy, would still result in severe climate change, with all its dire consequences: shifting climatic zones, freshwater shortages, eroding coasts, and ocean acidification, among others. Our reckoning showed that reversing the trend would require both radical technological advances in cheap zero-carbon energy, as well as a method of extracting CO2 from the atmosphere and sequestering the carbon.

Those calculations cast our work at Google’s REC program in a sobering new light. Suppose for a moment that it had achieved the most extraordinary success possible, and that we had found cheap renewable energy technologies that could gradually replace all the world’s coal plants—a situation roughly equivalent to the energy innovation study’s best-case scenario. Even if that dream had come to pass, it still wouldn’t have solved climate change. This realization was frankly shocking: Not only had REC failed to reach its goal of creating energy cheaper than coal, but that goal had not been ambitious enough to reverse climate change.