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A Memo from the Civil Society Institute:
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Howarth, Santoro, and Ingraffea key points (1/20/12):
1) Very urgent need to get methane emissions under control
globally, a point made by Jim Hansen and colleagues in 2007, but
made much more urgently by a 2011 report from the UN and a 2012
paper in Science by Shindell and colleagues of the NASA Goddard
Space Institute. Even if society were to take strong measures to
control carbon dioxide immediately, the planet would rise in
average temperature by 1.5 to 2 degrees within the next 15 to 35
years. This temperature rise puts the planet at great risk of
reaching a tipping point, and moving into a new and very different
climate system, with run-away global warming. Melting of permafrost
that releases yet more methane is just one potential tipping point,
among many.
2) Methane is an incredibly powerful greenhouse gas, and is already
a significant driver of observed global warming, second only to
carbon dioxide in its influence. Per mass, methane is far greater
in its global warming potential, but there is far less methane than
carbon dioxide in the air. And the methane does not stay in the
atmosphere as long, with a residence time that is some 10-fold less
than for carbon dioxide. This means that over the time period of
centuries ahead, carbon dioxide will have more impact than methane
(except for the consequences of methane in moving us into an
alternate climate system more quickly!). But at shorter time scales
(the integrated 20-year period following emission), methane is over
100
UNEP/ WMO (2011) and Shindell et al. (2012)
Without control of methane and BC, critical thresholds of 1.5o to
2o warming predicted in 15 to 35 years (even with aggressive CO2
control!!)
A Memo from the Civil Society Institute:
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times more effective as a greenhouse gas contributing than global
warming than is carbon dioxide, according to the most recent
science.
3) The most recent reports from the US EPA, as synthesized in the
Howarth, Santoro, and Ingraffea (2012) paper, show that methane
contributes 44% of the entire greenhouse gas inventory of the US,
when viewed through the lens of this 20-year period following
emission. Even when viewed over the integrated 100-year period,
methane makes up 19% of the greenhouse gas inventory of the US,
including carbon dioxide and all other greenhouse gases, from all
industries and human activities. And the natural gas industry is by
far the largest source of this methane from the US.
4) The emission of methane from natural gas activities includes
both purposeful venting of gas and accidental leakage. The exact
magnitude remains somewhat uncertain, but despite industry
assertions, most estimates for both conventional natural gas and
shale gas fall in a reasonably narrow range. The majority of
studies give estimates similar to the latest estimates from the US
EPA (which are far higher than the EPA was estimating as recently
as 2010, but are now increased due to better data than was
available back in 1996 when EPA last took a close look at methane
emissions from the oil and gas industry). Any of these emission
estimates are cause for great alarm, and the lowest numbers are
clearly biased or in error, as shown in the Howarth, Santoro, and
Ingraffea (2012) paper.
Latest information from U.S. national greenhouse gas
(Howarth et al. (2012), using EPA reports from 2011)
A Memo from the Civil Society Institute:
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Table 1. Comparison of published estimates for full life-cycle
methane emissions from conventional gas and shale gas, expressedper
unit of Lower Heating Value (gCMJ-1). Studies are listed by
chronology of publication date.Conventional gasShale gasHayhoeet
al. (2002)0.57*Jamarilloet al. (2007)0.15*Howarth et al. (2011)0.26
-0.96 0.55 -1.2EPA (2011a)0.380.60 +Jiang et al. (2011)*0.30Fulton
et al. (2011)0.38 ++*Hultman et al. (2011)0.350.57Skoneet al.
(2011)0.270.37Burnham et al. (2011)0.390.29Cathleset al. (2012)0.14
-0.360.14 -0.36See Electronic Supplemental Materials for details on
conversions. * Estimatesnot providedin thesereports.+Includes
emissions from coal-bed methane, and therefore may under-estimate
shale gas emissions.++ Based on average for all gas production in
the US, not just conventional gas, and so somewhat over-estimates
conventional gas emissions.
(Howarth et al. 2012)
5) Most of the recent studies on methane emissions from the natural
gas industry indicate that shale gas emits between 40% to 60% more
methane than does conventional natural gas. As conventional gas
reserves are depleted, and society turns increasingly to shale gas
as a replacement, methane emissions will increase.
A Memo from the Civil Society Institute:
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For the US, if Dept. of Energy predictions for gas supply sources
hold true, the increased use of shale gas by 2035 will increase the
contribution of methane from the natural gas industry from 17% to
24% of the entire greenhouse gas inventory of the country – all
gases, from all sources – when viewed through the 20-year lens.
6) Technical solutions for reducing (although not eliminating)
methane emissions from shale gas exist. For the methane venting
that occurs during the flowback period of a few weeks after a well
is fracked, gas can be captured and sold to market, if a pipeline
is in place and if the drilling company has invested in the
equipment to separate gas from frack liquid wastes. So far, most
companies have not followed this route, and at the current price of
natural gas, this would be a net cost for almost all wells fracked.
Only strong regulation will lead to this path.
7) Much of the leakage of methane to the atmosphere from the
natural gas industry comes from storage facilities, long-range
transmission pipelines, and local distribution pipes through urban
areas. Fixing these leaks may be extremely costly. Half of the
transmission pipelines in the US are more than 50 years old, and in
many cities, the local distribution pipes are older yet. In cities
such as Boston and Philadelphia, these locals systems often
pre-date the Great Depression of the 1930s, and are based on
unwelded cast iron pipe placed end-to-end with sealant that
probably gave out before World War II. Does it really make sense to
spend vast sums of capital to re-build this crumbling natural gas
system? Or should society instead invest in technologies for the
21st Century, such as smart grids