Open AccessAssessing the greenhouse impact of natural gas
Author(s) -
Cathles L. M.
Publication year - 2012
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2012gc004032
Subject(s) - natural gas , greenhouse gas , methane , fossil fuel , environmental science , coal , global warming , carbon dioxide , carbon leakage , fugitive emissions , leakage (economics) , carbon fibers , natural resource economics , environmental engineering , waste management , climate change , chemistry , geology , materials science , emissions trading , engineering , economics , oceanography , organic chemistry , composite number , composite material , macroeconomics
The global warming impact of substituting natural gas for coal and oil is currently in debate. We address this question here by comparing the reduction of greenhouse warming that would result from substituting gas for coal and some oil to the reduction which could be achieved by instead substituting zero carbon energy sources. We show that substitution of natural gas reduces global warming by 40% of that which could be attained by the substitution of zero carbon energy sources. At methane leakage rates that are ∼1% of production, which is similar to today's probable leakage rate of ∼1.5% of production, the 40% benefit is realized as gas substitution occurs. For short transitions the leakage rate must be more than 10 to 15% of production for gas substitution not to reduce warming, and for longer transitions the leakage must be much greater. But even if the leakage was so high that the substitution was not of immediate benefit, the 40%‐of‐zero‐carbon benefit would be realized shortly after methane emissions ceased because methane is removed quickly from the atmosphere whereas CO 2 is not. The benefits of substitution are unaffected by heat exchange to the ocean. CO 2 emissions are the key to anthropogenic climate change, and substituting gas reduces them by 40% of that possible by conversion to zero carbon energy sources. Gas substitution also reduces the rate at which zero carbon energy sources must eventually be introduced.