Two Engineering Measures to Reduce Global Warming: Injecting Particles into the Atmosphere and "Clean" Coal

Managing Incoming Solar Radiation
Largely out of concern that society may fall short of taking large and rapid enough measures to effectively contain the problem of global warming, two prominent atmospheric scientists - Paul Crutzen, who won a Nobel Prize in chemistry in 1995, and Tom Wigley, a senior scientist at the National Center for Atmospheric Research - published papers in 2006, suggesting that society might consider using geoengineering schemes to identify a temporarily "fix" to the problem.
The concept of geoengineering - deliberately using technology to modify Earth's environment - has been discussed in the context of climate change since at least 1960. Over the years, proposals have included everything from carbon sequestration through ocean fertilization to damming the oceans. Crutzen and Wigley argued that geoengineering schemes, if done continuously, could reduce global warming enough to buy society time to address mitigation. However, geoengineering schemes may not be the answer. And in fact, such measures have the potential to create more problems than they solve.
In particular, Crutzen and Wigley focused on blocking incoming solar radiation, an idea that has generated much interest in the press and the scientific community. Nature offers an example of how to do this. Volcanic eruptions cool the climate for up to a couple of years by injecting precursors to sulfate aerosol particles into the stratosphere, which has the effect of temporarily blocking incoming sunlight. It is true that volcanic eruptions cool the climate, but their effects are not innocuous, and should serve as a warning to society to be very cautious about deploying such geoengineering “solutions” without careful and considered evaluation beforehand. Among other things, the particles from volcanic eruptions also cause ozone depletion.
Clean Coal Technology and Future Prospects
Clean coal technologies are real, commonly used in commercial industrial gasification and likely essential to reduce CO2 due to the fast growing use of coal worldwide, especially in China. Commercial example of clean coal technology in the USA is the 25 year-old coal to synthetic natural gas (SNG) plant in North Dakota where all of the CO2 is captured and most is geologically storage for use in enhanced oil recovery (EOR) in Canada.
The key issue is expanding clean coal technologies into coal-based electric power generation. This expansion presents additional challenges - more technology options and higher cost of CO2 capture than for industrial gasification. This also requires large-scale demonstration of all three CO2 capture technology options: pre, post and oxygen combustion. In time, the CO2 capture and storage costs will be reduced by both “learning by doing” and developing advanced technologies already moving in to small-scale demonstrations.
Biographies
Dr. Alan Robock is a Distinguished Professor of atmospheric science in the Department of Environmental Sciences at Rutgers University and the associate director of its Center for Environmental Prediction. He also directs the Rutgers Undergraduate Meteorology Program. He graduated from the University of Wisconsin, Madison, in 1970 with a B.A. in Meteorology, and from the Massachusetts Institute of Technology with an S.M. in 1974 and Ph.D. in 1977 in Meteorology. Before graduate school, he served as a Peace Corps Volunteer in the Philippines. He was a professor at the University of Maryland, 1977-1997, and the State Climatologist of Maryland, 1991-1997, before coming to Rutgers.
Dale Simbeck joined SFA Pacific in 1980 as a founding partner. His principal activities involve technical, economic and market assessments of energy and environmental technologies for the major international energy companies. This work includes electric power generation, heavy oil upgrading, emission controls and synthesis gas production plus utilization.