Post on 28-Dec-2015
Natural Gas, Methane, and Global Warming
Robert HowarthThe David R. Atkinson Professor of Ecology & Environmental Biology
Cornell University, Ithaca, NY USA
January 28, 2014
(Hayhoe et al. 2002)
For just the release of carbon dioxide during combustion…..
Is natural gas a “bridge fuel?”
Natural gas 15
Diesel oil 20
Coal 25
g C of CO2 MJ-1 of energy
Methane emissions – the Achilles’ heel of natural gas
• Natural gas is mostly methane.
• Methane is 2nd most important gas behind human-caused global warming.
• Methane is much more potent greenhouse gas than carbon dioxide, so even small emissions matter.
Carbon Dioxide Methane
Marcellus Well Being “Finished” Marcellus Well Being “Finished” Outside Dimock, PA, June 2011Outside Dimock, PA, June 2011
Photo and FLIR Methane-Tuned Video Courtesy Frank Finan
Video
http://www.loe.org/shows/segments.html?programID=12-P13-00002&segmentID=3
Bruce Gellerman, “Living on Earth,” Jan. 13, 2012, based on work of Nathan Phillips
Pipeline accidents and explosions happen, due to large leaks…. ….. small leaks are ubiquitous.
Flames consume homes during a massive fire in a residential neighborhood September 9, 2010 in San Bruno, California. (Photo by Ezra Shaw/Getty Images)
Pipelines in US are old!
PHMSA 2009 Transmission Annual Data
0
15
30
45
60
75
Low Estimate High Estimate Low Estimate High Estimate Surface-mined Deep-Mined
Shale Gas Conventional Gas Coal Diesel Oil
Gra
ms C
arbo
n pe
r MJ
Methane
Indirect CO2
Direct CO2
20-year time frame
Howarth et al. 2011
highmethane
highmethane
low methane
low methane
surfacedeep
Shale Gas Conventional Natural Gas
Coal Oil
0% 3% 6% 9% 12%
4
3
2
1
0
Percent methane emission from natural gas
Gre
enho
use
gas
emis
sion
s re
lativ
e to
coa
l
Greenhouse gas consequences for natural gas compared to coal(compared over integrated 20-year time frame)
Better than coal
Worse than coal
ElectricityEPA 2011
Howarth et al. 2011
Extrapolated from NOAA studies
Coal-powered plant
Natural gas
electricity
Heat pump
Gas burner
Domestic hot water heating
0% 3% 6% 9% 12%
4
3
2
1
0
Percent methane emission from natural gas
Gre
enho
use
gas
emis
sion
s re
lativ
e to
coa
l
Greenhouse gas consequences for natural gas compared to coal(compared over integrated 20-year time frame)
Better than coal
Worse than coal
Electricity
Hot water
EPA 2011
Howarth et al. 2011
Extrapolated from NOAA studies
Water heated by natural gas has a very large
greenhouse gas footprint
http://news.discovery.com/earth/alaskas-arctic-tundra-feeling-the-heat.html
1.5 oC threshold
2.0 oC threshold
Dangerous tipping points are only 15 to 35 years into the future.
Controlling methane is CRITICAL to the solution!
Shindell et al. 2012
(Howarth et al. 2012, based on EPA (2011)
US National Methane Emissions for 2009
Thanks for the invitation to participate.
Special thanks to Tony Ingraffea, Bongghi Hong, and Drew Shindell.
Funding: Park Foundation Wallace Global Fund Cornell University
Shale gas…. A bridge to nowhere