Kyoto is such a joke.
It's actually the flatulent cows that we need to blame:
rucus.ru.ac.za
Cow flatulence: a significant contributor to global warming or just a load of hot air?
Seranne Howis
Rhodes University, Department of Botany, Grahamstown, 6140
Note: I recently received an email of rebuttal to this essay, found here.
Greenhouse gases and global warming
Life on Earth is linked to the presence of atmospheric trace gases and the effect their concentrations have on the climate. Although their concentrations are small compared to oxygen and nitrogen (the major atmospheric constituents), they have a substantial impact on the climate, due to the significant amount of interaction they have with infrared (long-wave) radiative energy (Roeckner, 1992).
When radiant energy from the sun reaches the Earth, some is reflected back into space, the amount of which is dependent on the planet's albedo. The radiative energy that is not reflected passes through the various layers of the atmosphere and is absorbed by the Earth. At night, some of that absorbed radiative energy is re-radiated out into space, and of that energy some is again bounced back to the Earth by the atmosphere.
The concentrations of trace gases determine how much energy is radiated back to the Earth and how much escapes into space. Energy balance equations show that without this natural greenhouse effect, the global mean surface temperature would be approximately 33K colder than it is at present, provided the albedo of the Earth remained the same (Roeckner, 1992).
The greenhouse effect on the Earth is generated mostly by water vapour, which is abundant and opaque to infrared radiation and contributes about 65% to the greenhouse effect (Potenza, 2000). 33% of the greenhouse effect is contributed by carbon dioxide, while the remaining 2% is due to the other greenhouse gases: ozone (O3), methane (CH4) and nitrous oxide (N2O) (Potenza, 2000).
Despite this difference in relative quantities, each gas has different abilities to reflect and trap heat. Methane is capable of trapping 25 times more heat than CO2, and is expected to cause between 15 and 17% of the global warming over the next 50 years (Adam, 2000). And whilst carbon dioxide emissions can persist for over a century,
methane in the atmosphere breaks down within a decade. This suggests that reducing methane emissions will have a more immediate impact on global warming (Adam, 2000). CO2 had increased by 30% in the last 200 years, whilst methane has doubled in that time period.
"Artificial" methane emissions come from various sources, such as power stations, coal mining, but nearly 50% of methane comes from agriculture. Rice agriculture is a contributor, but anywhere from 20% to 60% of 'man-made' emissions originate from livestock (Adam, 2000; Major, 2000).
Methanogens
Bacteria in the stomachs of cows (and other ruminant animals) break down and ferment fodder during digestion, producing methane (Adam, 2000). The initial steps are performed either by facultative anaerobic bacteria (such as E. coli which convert formate to H2 and CO2) or by obligate anaerobes (Clostridium or Selenomonas which do similar conversions) (College, 1999).
Methanogenic archaebacteria (a group separate from true bacteria) are obligate anaerobes that are very sensitive to oxygen and prefer environments without any other electron acceptors such as nitrogen (Beckmanm, 2000; College, 1999). They perform the final steps in the fermentation and they convert H2 and CO2 produced by the other organisms to methane by the following equation:
4 H2 + CO2 --> CH4 + 2 H2O + ATP
or they can convert acetic acid to make methane as below:
C2H4O2 --> CH4 + CO2 + ATP
This CO2 can further be used in the first equation to make more methane (Morris, 1998). Approximately 90 – 95% of the CO2 is converted to methane, and the energy derived is used to fix the remaining CO2 into cellular materials (College, 1999). Strictly speaking, this methane formation action by the methanogens is not a fermentation (as there is no substrate level phosphorylation and ATP is generated via the methane formation pathway), but is rather a strange form of respiration (College, 1999).
These methanogens are present in ruminant animals other than cows, such as sheep and wildebeest. Approximately 10 percent of humans have these methanogens in their guts as well (probably inherited from their parents) (Beckmann, 2000).
Cow flatulence
It has been estimated that 9 to 12% of the energy that a cow consumes is turned to methane that is released either through flatulence or burping (Radford, 2001). A huge number of factors affect methane emission, including diet, barn conditions and whether the cow is lactating, but an average cow in a barn produce 542 liters of methane a day, and 600 liters when out in a field (Adam, 2000).
These estimates were made using a trace gas (sulphur hexofluoride) that was released at known points within a barn containing 90 cattle. Levels of this trace gas and CO2 are then measured 30 metres downwind of the shed and thus they can estimate how much CO2 is released per cow per day. All this methane can add up to a significant amount. Australia's 140 million sheep and cattle are estimated to produce one seventh of the nation's total greenhouse gas emissions, whilst America's 100 million cattle also are major contributors (Major, 2000).
Reducing methane production
The Kyoto treaty is aimed at reducing CO2 emissions, which make it costly and impractical to implement and it has been suggested that reducing methane production is much more economical as methane emissions are not economically necessary (DeCorla-Souza, 2001).
Suggestions as to means to reduce this production include genetically engineering cattle, the bacteria they carry that produce the methane or altering their feed. Improved management of animals in extensive grazing systems and protected feeds are other suggestions aimed at reducing methane production. The duel aims of all of these methods are to reduce methane production at the same time as increasing production.
There has been some development of a vaccine that alters the population of microorganisms in the animal's stomach and vaccine discourages methanogenic archaea (Major, 2000).
The altering of their feed seems to be the easiest course and can either be by means of feeding the cattle less "volatile" fodder (Radford, 2001) or by adding substances to the feed. The addition of a bacterium to cow feed has shown some small scale success, using a bacteria that uses oxygen to convert methane into carbon dioxide and in doing so, it stimulates the microbial activity in the animal's gut that aid the digestive processes, thus leading to a more productive cow (Chang, 2000).
Conclusion
With the strong focus by environmentalists on reducing CO2, it seems that methane emision reduction has been pushed aside, when it could be an easier, quicker and cheaper method of reducing greenhouse gases (DeCorla-Souza, 2001). Current suggestions to impose a "methane tax" on cattle farmers has been met with cries of protest from said cattle farmers, who prefer to investigate alternative methods to reduce methane production (ideally those that also provide a boost of some sort to cattle production). |
