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Two Engineering Measures to Reduce Global Warming: Injecting Particles into the Atmosphere and "Clean" Coal
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What is geoengineering? How might injecting sulfate aerosol particles into the stratosphere result in a temporary planetary cooling? Would this be analogous to creating the equivalent of a long-term volcanic eruption? Would this be a permanent solution to a global warming or an exercise in buying time to effectively address the root cause of the climate problem? What is the logic behind it and what are the mechanics of it? What sorts of policies would likely have to be in place in order to engage in such a venture? Who decides and who is liable if things go awry? Does science inform us of the potential risks and negative impacts of engaging in such a venture? Is clean coal and carbon capture and storage one and the same? What is meant by the term ‘clean’ in clean coal? Does the technology currently exist to produce clean coal on a massive scale and if so, at what cost relative to today’s energy costs. What are the risks of leakage of CO2 from underground storage reservoirs after the fact? Who is likely to be liable for leakage? How much of a difference would clean coal technology ideally make in mitigating our present climate trajectory?
Dr. Anthony Socci, Senior Science Fellow, American Meteorological Society
Alan Robock, Distinguished Professor of Atmospheric Science; Director of the Meteorology Undergraduate Program, and Associate Director, Center for Environmental Prediction, Department of Environmental Sciences, Rutgers University, New Brunswick, NJ
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 schemes were suggested as an interim measure intended to buy time to prevent the worst damage from global warming while society used that time to identify and deploy measures to address the root cause of the problem. Such suggestions however, are not new.
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. Furthermore, reducing solar radiation also reduces evaporation, and hence precipitation, more than warming by greenhouse gases increases precipitation. Thus, checking the temperature (incoming solar radiation) with aerosols actually reduces global average precipitation.
Furthermore, the cooling from such measures is not uniform. In the Northern Hemisphere, aerosols cause more cooling over the Eurasian continent than over the oceans in the summer, thus reducing the strength of the Asian summer monsoon, which provides rain to grow the food supply for billions of people. Reductions in rain have historically been observed after major volcanic eruptions, but they only last a year or two, and do not have long-lasting consequences. With continuous geoengineering, however, these effects would persist for years.
There are other reasons to be concerned about “solar radiation management.” There would be less solar radiation for solar power, especially for systems requiring direct radiation. Plant growth would be affected in still unknown ways. And by not dealing directly with greenhouse gas emissions, carbon dioxide would continue to accumulate in the oceans and the atmosphere, resulting in more ocean acidification and the continued build up of more climate-warming greenhouse gases in the atmosphere. Furthermore, if such geoengineering were to stop precipitously, as a result of failures of technology, societal will or capability, warming would likely be exceptionally rapid, as these measures treat the symptoms of a warming climate and not the root causes. The rate of climate change is also one of the most important disrupting factors.
Even if geoengineering proved effective in the short term, whose hand would be on the thermostat? Who would be held liable if the experiments went awry? Furthermore, it is possible that the world could not agree on an optimal temporary cooling. What if Russia, for example, wanted the temperature to be a couple of degrees warmer and India a couple degrees cooler? And who would arbitrate? Should this temporary cooling effect set the planetary temperature to the pre-industrial value or keep it constant at today's temperature? Would it be possible to tailor the climate of each region of the planet independently without affecting the others? Current scientific understanding of these issues says no. Consequently, if society proceeds with geoengineering schemes, might it also be setting the stage for climate wars of the future?
One of the most important concerns among many is that schemes perceived to temporarily cool the planet will lessen the incentive to mitigate greenhouse gas emissions or worse, give the impression of being permanent solutions to the root causes of climate change. Yes, geoengineering research should continue. Society desperately needs to better understand the efficacy and potential problems related to such measures. Unfortunately, there are no current US research programs on geoengineering, nor any funding for such programs. At some point society may well need to consider geoengineering as an emergency stop-gap measure, but such a decision should be informed by modeling studies to better assess the potential impacts and the dangers involved. However, even if geoengineering measures are deployed, society would be remiss to fall into the trap of equating treating the symptoms of the problem with measures that serve to mitigate the root causes of the problem. The more headway society is capable of making in the realm of mitigating climate change, the less likely society might need to deploy interim geoengineering measures.
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.
The way forward is likely to focus on CO2 capture and storage (CCS) based on rebuilding the old, paid-off, lower efficiency and relatively dirty coal power plants in the USA. This approach can avoid capacity and efficiency loses of CCS while at the same time greatly reducing all emissions.
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.
Dr. Robock has published more than 250 articles on his research in the area of climate change, including more than 150 peer-reviewed papers. His areas of expertise include geoengineering, regional atmosphere-hydrology modeling, climatic effects of nuclear weapons, soil moisture variations, the effects of volcanic eruptions on climate, detection and attribution of human effects on the climate system, and the impacts of climate change on human activities.
Dr. Robock is a Fellow of the American Meteorological Society and President of the Atmospheric Sciences Section of the American Geophysical Union. He has been a Member Representative for Rutgers to the University Corporation for Atmospheric Research since 2001, and serves on its President's Advisory Committee on University Relations. Dr. Robock is also the American Meteorological Society/Sigma Xi Distinguished Lecturer for the academic year 2008-2009, and is a contributor to the Intergovernmental Panel on Climate Change, which was awarded the Nobel Peace Prize in 2007.
During his first sabbatical in 1986-1987, Dr. Robock was a AAAS Congressional Science Fellow. At that time he served as a Legislative Assistant to Congressman Bill Green (R-NY), and as a Research Fellow for the Environmental and Energy Study Conference.
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.
Mr. Simbeck’s work on the global climate change issue includes a private multiclient analysis of greenhouse gas mitigation options for over 30 major international energy companies. Among a host of things, he was a lead author of the 2005 IPCC Special Report on CO2 Capture and Storage (CCS). He is also an advisor to the CO2 Capture Projects (CCP-1&2) and the Canadian Clean Power Coalition (CCPC). His public assistance on this important issue includes work for the United Nations, World Bank, the Global Environmental Facility (GEF) and the Governments of Canada, China and the United States.
Mr. Simbeck is a Chemical Engineering graduate of Pennsylvania State University. He has also assisted the Engineering Department of Stanford University as a Ph.D. advisor and Massachusetts Institute of Technology as a member of the External Advisory Broad to the MIT Energy Lab. Dale is a Registered Professional Engineer in California and has made numerous presentations on the technical and economic challenges of CO2 mitigation and clean coal technology. His peer reviewed papers on CO2 mitigation are mostly for the 1998-2006 International Conference on Greenhouse Gas Technologies (GHGT), including a technical session keynote at the GHGT-9 in Washington, DC. November 17, 2008.
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This seminar series is open to the public and does not require a reservation.
The Next Seminar is tentatively scheduled for the third week in January, 2009.
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