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Dr. Robert Howarth
Department of Ecology and Evolutionary Biology, Cornell University (USA)
Robert Howarth is a biogeochemist and ecosystem biologist. He joined the faculty at Cornell University in 1985 and was appointed the David R. Atkinson Professor of Ecology & Environmental Biology in 1993. For the past 35 years he has run an active research program focusing on how human activity affects the environment, with emphases on global change and on coastal ocean water quality. A particular emphasis is human alteration of the nitrogen cycle at scales from local to regional to global, including both sources of pollution and their consequences. Howarth also works on greenhouse gas emissions (particularly methane and nitrous oxide) and the ecological consequences of oil and gas development. He earned a BA in Biology from Amherst College in 1974 and a Ph.D. jointly from the Massachusetts Institute of Technology (MIT) and the Woods Hole Oceanographic Institution in 1979. Howarth is the Founding Editor of the journal Biogeochemistry and was Editor-in-Chief of the journal from 1983 to 2004. He chaired the National Academy of Sciences Committee on Causes and Consequences of Coastal Marine Eutrophication from 1998-2000, co-chaired the International SCOPE Nitrogen Project from 1992 to 2002, directed the North American Nitrogen Center of the International Nitrogen Initiative from 2003-2006, and has been chair of the International SCOPE Biofuels Project on environmental effects of biofuels since 2007. He is a consultant to the United Nations Environment Program on sustainable resource use, and has served on 10 other panels and committees of the National Academy of Sciences, including one on oil pollution and one on trace gases and global change. In 2011, he published the first comprehensive analysis of the greenhouse gas footprint of shale gas in Climatic Change Letters and an invited commentary on shale gas in Nature. He has published over 200 scientific papers, reports, and book chapters.
Only in the past 10-15 years have high-volume hydraulic fracturing and precision directional drilling been combined to make extraction of natural gas from shale commercially viable. Industry and many governments promote shale gas, often describing shale gas as a bridge fuel that allows continued use of fossil fuels while reducing greenhouse gas emissions (GHG) compared to other fuels. In April 2011, we published the first comprehensive analysis of the GHG footprint of shale gas, concluding that in fact full-lifecycle GHG emissions from shale gas are comparable to or larger than those from oil and coal. Since our paper was published, the US EPA issued new estimates on GHG emissions from natural gas systems, and many other papers and reports have also evaluated aspects of the GHG footprint of shale gas. In February 2012, we published a paper synthesizing and summarizing this new information. In this talk, I will further update the rapidly changing state of knowledge on the GHG footprint of shale gas.
Methane venting and leakage dominates the GHG footprint of shale gas, particularly when considered using the most recently available information on global warming potential that integrates the effect of methane over a 20-year time period. The influence of methane is diminished at the 100-year time frame. Over a wide range of estimates of methane emission, the GHG footprint of shale gas is worse than other fossil fuels, when viewed at the 20-year scale. The most recent evidence suggests that many studies continue to underestimate the magnitude of methane emissions.