Update and Recent Comments on World Watch Article
Posted Tuesday, January 12, 2010 at 10:41 AM
Update and Recent Comments on World Watch Article That Argues that Livestock Sector Causes At Least 51% of Human-Caused Greenhouse Gas Emissions
update by Robert Goodland (co-author of the original article) on the article in World Watch is at http://www.wellfedworld.org/PDF/FAOConsult12-09.pdf
Below are comments on the original article by Australia's Geoff Russell (who's been a co-author with Peter Singer on various material) -- which seems to have helped him get to the point of posting a column yesterday excerpted as follows (and visible in its entirety at http://theenergycollective.com/TheEnergyCollective/55860):
Is livestock consumption exceeding plant growth?
In my last BNC post, I referred to an estimate just published as a WorldWatch report that put the impact of livestock on greenhouse forcings at about 51 percent [actually at least 51%, according to the article] of the global anthropogenic total. I didn't analyse this figure, but suggested it wasn't unreasonable to think that land clearing, feeding, watering, housing, slaughter, transport and cooking implicit in dealing with 700 million tonnes of livestock biomass could conceivably be responsible for half of the total climate impact of 335 million tonnes of human biomass. But I was waiting for more expert analysis and still am. Many of the additions over and above the 2006 Livestock's Long Shadow (LLS) estimate rely on close knowledge of the precise details of the FAO's statistical data collection processes.
But on theoretical grounds, one of the most contentious inclusions in the 51 percent figure is livestock respiration¦ the carbon dioxide that livestock exhale. On the face of it, this seems plain wrong. All of the carbon dioxide in livestock respiration comes from the atmosphere via photosynthesis in plants. So it's simply part of the carbon cycle. Isn't it? The WorldWatch authors have subsequently justified this a little further, re-citing evidence given in LLS which states that animal respiration plus soil carbon oxidation (co2 flowing into the atmosphere) exceeds the drawdown due to photosynthesis by one or two billion tonnes of carbon annually. In many cases it is livestock driving the loss of soil carbon by deforestation and desertification and given that the planet's 700 million tonnes of livestock dwarf wildlife by a ratio of about 23:3, it is possible that the planet's total plant biomass may be shrinking under livestock's onslaught. This is the implication of the reduction of NPP noted above and the carbon flow imbalance just mentioned.
I say may be shrinking because it's tough to measure things like global photosynthesis or global respiration, and the figures in LLS are not the same as the figures in the Austrian work. Close, but not the same. But if the respiration plus soil carbon losses really are outstripping photosynthesis, then including at least some livestock respiration in the ledger isn't just reasonable, but mandatory.