[Vision2020] Ed the Viking, Greenland, and Global Warming

[Ted Moffett]

Nick wrote:

>
> Regarding livestock and global warming, they contribute, by expelling
> methane, 18 percent of all greenhouse gases, more than all world transport
> combined.  In developing countries raising cattle also requires burning
> forests, which overall contributes another 18 percent of greenhouse gases.


Can you provide scientific references for the data you offer above?  I am
finding documentation of this data difficult.

Methane releases from livestock do not add up to 18 percent of greenhouse
gases from human activity or 18 percent of the human sourced greenhouse
effect, given the sources I've read.

A source listed below gives methane releases in the USA, many from non
agricultural sources (landfills, coal mines, oil and gas operations) as 9
percent of total human sourced greenhouse gases.  The amount from livestock
would be a fraction of this amount.

The GWP (global warming potential) would need to be considered, given that
methane is a more powerful greenhouse gas than CO2, though it dissipates in
the atmosphere much faster. I wonder if this 9 percent figure is corrected
for GWP.  Of course this is only data for the USA, so global percentages of
methane release could be very different:

http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html

According to this source below, significant methane releases are associated
with the huge increase in rice cultivation (anaerobic decomposition in
paddies):

http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/co2_change.html

NASA article claiming rice cultivation adds 8 percent of total global
methane releases, or it did till recent changes, much of this coming from
China:

http://www.gsfc.nasa.gov/topstory/2002/1204paddies.html

This source below (asserting CO2 is 80 percent of the human sourced
greenhouse effect) combined with other data I've read on the percentages of
atmospheric concentration of other greenhouse gases, suggests methane from
all human impacts contributes about 10 percent of the current human sourced
greenhouse effect, allowing for GWP.  Even if this figure is in error, I
doubt that just the methane from livestock will equal 18 percent of the
human sourced greenhouse effect, given the percentage influence of CO2,
nitrous oxide, carbon monoxide, CFCs, etc. and methane from other sources:

http://www.nature.com/nature/journal/v344/n6266/abs/344529a0.html

Another source below gives a figure for methane's GWP over the next hundred
years as 18 percent of the total human impact, but the amount of methane
from fossil fuel related and waste treatment and disposal sources is a large
percentage of this total. Consider that even if methane contributes 18
percent to the GWP, in absolute amount of percentage of release it is at
a much smaller level, because it is a more powerful greenhouse gas than the
dominant greenhouse gas from human sources, CO2.  This source is data from
2000, and fossil fuel use has increased dramatically in the past 6 years,
thus the 14 percent figure for the transportation sector is now in error:

http://en.wikipedia.org/wiki/Image:Greenhouse_Gas_by_Sector.png

As far as burning of forests contributing 18 percent of atmospheric CO2 from
human impacts, I cannot verify this figure either.  The source above gives a
figure of 10 percent of greenhouse gas emissions for land use and biomass
burning, which should include forest burning impacts.  This source below
gives a figure from burning of forests and deforestation of 7-10 percent of
the CO2 emissions from fossil fuels:

http://www.stanford.edu/dept/news/pr/2004/biomass-812.html

Quote from article above:

Of forest burning, about 80 percent results in permanent deforestation -
meaning the land is now used for some other use, such as grazing,
agriculture or buildings. The remaining 20 percent of trees are regrown.
When forests are permanently replaced by other plant types - shrubs,
grasses, crops, all of which contain less carbon than do trees - the carbon
difference accumulates in the atmosphere. "The total carbon dioxide emission
from permanent deforestation is on the order of 7 to 10 percent of global
fossil-fuel-carbon-dioxide emission," Jacobson says.

Jacobson's calculations used a model honed over 14 years and emission data
from a variety of sources. He is an author of two textbooks - Fundamentals
of Atmospheric Modeling (Cambridge University Press, 1999) and Atmospheric
Pollution: History, Science, and Regulation (Cambridge University Press,
2002).

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Given these estimates of methane releases from livestock in absolute
amounts, and in terms of the GWP of these methane releases, methane from
livestock does not equal the amount of CO2 from the transport sector, which
according to the source below contributes over 18 percent of global human
sourced CO2 emissions, nor does it equal this CO2s GWP.

http://earthtrends.wri.org/updates/node/135

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Vision2020 Post: Ted Moffett
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