Dr Tom Wigley was educated as a mathematical physicist and earned his doctorate at the University of Adelaide, Adelaide, South Australia, Australia. He served as director of the Climatic Research Unit at the University of East Anglia in the United Kingdom from 1978 to 1993. In 1993 he went on to the National Center for Atmospheric Research in Boulder, Colorado, where he was appointed a senior scientist in 1994. He is a climate scientist at the University Corporation for Atmospheric Research (UCAR). He was named a fellow of the American Association for the Advancement of Science (AAAS) for his major contributions to climate and carbon cycle modeling and to climate data analysis, and because he is "one of the world's foremost experts on climate change and one of the most highly cited scientists in the discipline". Dr. Wigley joined the University of Adelaide in Australia in 2012 as a Professor (see: http://en.wikipedia.org/wiki/Tom_Wigley and http://www.zoominfo.com/p/Tom-Wigley/4220024 ).
Professor Tom M.L. Wigley on “Coal to gas” the influence of methane” (National Center for Atmospheric Research, Boulder, CO, 80307-3000, USA and University of Adelaide, Adelaide, South Australia, Australia) (2011): “Abstract: Carbon dioxide (CO2) emissions from fossil fuel combustion may be reduced by using natural gas rather than coal to produce energy. Gas produces approximately half the amount of CO2 per unit of primary energy compared with coal. Here we consider a scenario where a fraction of coal usage is replaced by natural gas (i.e., methane, CH4) over a given time period, and where a percentage of the gas production is assumed to leak into the atmosphere. The additional CH4 from leakage adds to the radiative forcing of the climate system, offsetting the reduction in CO2 forcing that accompanies the transition from coal to gas. We also consider the effects of: methane leakage from coal mining; changes in radiative forcing due to changes in the emissions of sulfur dioxide and carbonaceous aerosols; and differences in the efficiency of electricity production between coal- and gas-fired power generation. On balance, these factors more than offset the reduction in warming due to reduced CO2 emissions. When gas replaces coal there is additional warming out to 2,050 with an assumed leakage rate of 0%, and out to 2,140 if the leakage rate is as high as 10%. The overall effects on global-mean temperature over the 21st century, however, are small.” [1].
[1}. Tom M.L. Wigley, “Coal to gas” the influence of methane”, Climatic Change, October 2011, Volume 108, Issue 3, pp 601-608: http://link.springer.com/article/10.1007%2Fs10584-011-0217-3 .