Stephen Walsh’s fourth and final criticism of Livestock and Climate Change (LCC) is as follows:
“The fourth key flawed assumption in the Worldwatch article is that opportunities to absorb CO2 through alternative uses of land that is currently used to feed livestock should be added to emissions from fossil fuels and deforestation and counted as part of the total emissions due to livestock.” (Emphasis in original.)
In other words, objecting to something that is going on (which would be appropriate) is different from objecting to something that is not going on, but could be made to happen, if we wanted to. Walsh illustrates what he means by this example: “We could argue that the most effective use of land from a global warming perspective is to cover it with solar panels to replace fossil fuel generation of electricity. The reduction in emissions per hectare per year would be about 200,000 kg CO2e compared with about 10,000 kg for reforestation.”
This is essentially a semantic argument. If we stop grazing animals or growing crops on that land, is this an “alternative use” for the land? Or is it just “not doing what you were previously doing”? Clearly, ceasing livestock agriculture on a piece of land is in a completely different category than covering it with solar panels. Building solar panels requires active intervention, mobilization of the appropriate metals, further use of fossil fuels, and mobilization of workers and factories to support all of this. But in the case of livestock, in many cases much of the land devoted to livestock will revert to forest of its own accord.
So all we have to do, is to stop doing what we are now doing. It’s more like shutting down a coal plant than building solar panels.
Walsh then describes three problems with LCC’s approach. The first two problems just restate his basic point, while the third problem raises an entirely different issue, that “the actual impact of land use change on global warming is complex.” This is true enough, but not directly relevant — GHG emissions which are hard to understand do not, simply by virtue of being complex, become either lost opportunities or direct emission sources.
Walsh then, in passing, makes an intriguing statement. We could in fact do reforestation of the tropical rain forests that have been cut down for livestock grazing: “Such an immense but technically possible level of tropical reforestation could offset about 11% of the current global fossil fuel emissions over the next fifty years. Once the forest is mature it is questionable whether the benefit can be sustained.”
It’s interesting that this 11% figure for reforestation is very close to the LCC estimate for livestock respiration of 13.7% — which in fact Goodland suggested on the WorldWatch discussion forum was a “proxy” for the carbon lost due to deforestation. In other words, at least for the next 50 years, Walsh and LCC differ by just 2.7% — and if you include temperate forests, Walsh may in fact largely agree with LCC on this issue.
Then in an offhand way Walsh raises another question, does a mature forest continue sequestering carbon? (Steve Kaufmann also raised this issue more explicitly on the WorldWatch discussion forum.) It’s plausible that the benefit would stop or would be substantially less. It’s also plausible that it might continue. Does anyone know any actual research on this question?
The biomass in the trees certainly reaches a maximum point in a climax forest, but there’s a lot going on underneath the ground that we don’t know about. When the Europeans came to America, they cleared forests and found topsoil many feet thick. It takes 100 to 1000 years to form an inch of topsoil, and who knows how much organic carbon in each inch. This probably did not occur just in the relatively brief time (perhaps a century) that it took for the forest to reach maturity. One would suspect that some carbon sequestration continues even in a mature forest, at least in temperate zones.
Walsh’s fourth criticism does not give us reason for rejecting the thesis of LCC. Rather, it seems actually to support the conclusions of LCC, but seeking to rephrase those conclusions in a perhaps more “politically correct” way.