Allan Savory on desertification and climate change

Allan Savory gave this talk in Ireland in November 2009. About 58 minutes.

Allan Savory - Keeping Cattle: cause or cure for climate crisis? from Feasta on Vimeo.

Comments

Savory's usual reasoned and methodical approach, here, based on his unique experience. Listenable and informative.

Around minute 53, he claims 100,000 cars per year emissions equals approximately a 12 acre grassland fire burning for 15 minutes. No doubt, burning causes enormous emissions, but my numbers don't come close to his. I'm estimating that only a few tons of dry hay or straw get bailed per acre, and some fraction of a ton of fuel is burned per car annually. A few dozen tons of hay as fuel is at least an order of magnitude less than a couple thousand tons of gasoline. Is there something to account for the difference, or is he simply overstating or mistaken?

Glenn

Glenn, good question, the relevant passage is at about minute 35.

I'm not privy to his arithmetic, but I suspect Savory is including methane and nitrous oxide emissions from fire, and possibly black carbon as well, and converting to CO2 equivalents. And certainly the fire pictured is oxidizing a fair amount of tree carbon.

Fire regimes no doubt have enormous variability in terms of their emissions, and their effects on the overall carbon cycle. Not a lot of monitoring has been done.

Forest service research after the 2002 Biscuit Fire in southwest Oregon, in which previously studied research plots were burned, showed about 10 tons of soil carbon and 450-620 pounds of nitrogen per acre was lost because of the fire. What was surprising to most was that most of the loss of both C and N was from the mineral horizons of the soil, not the surface duff layer, which of course was consumed entirely. In addition, about an inch of soil (127 tons per hectare) apparently went into the smoke plume ("fire-driven convective erosion" in the words of the paper cited below). Other fire studies have shown significant emissions of N2O which is around 300 times CO2 in greenhouse effect.

http://www.fs.fed.us/pnw/news/2008/10/soil-wildfires.shtml (click link at bottom to access the paper, then at the upper left to get a pdf version)

Many people assert that emissions from fire are recaptured biologically, so that there is little net addition to the atmospheric load from fire. However, what they are missing is the undue acceleration of the carbon cycle, particularly from regular savanna burning or crop residue burning. The ability of plants and soils to hold carbon out of the atmosphere is deeply compromised. In business, the timing of cash flows has huge impacts on viability and the ability to increase profit, and so it is with the carbon cycle. Imagine what our real estate landscape would look like if all loans had to be repaid within the year.

NASA researcher Joel Levine estimates that about a quarter of the airborne fraction of CO2 is from biomass fire. Though poorly formatted for the web, the following article will be a shocker to many people:

http://asd-www.larc.nasa.gov/biomass_burn/globe_impact.html

Likewise water holding capacity of soils is compromised. The constant baring of soil can be very destructive to soil microorganisms. Where there is no litter, there is less feedstock for humification and the formation of stable soil organic matter. Overall biodiversity is compromised, as carbon is recycled through combustion rather than decay which is much slower and requires and feeds an enormous range of organisms.

Many people will also assert that certain species depend on fire to release seeds, etc. and that therefore the "ecosystem needs fire." Some species are indeed fire-adapted, but the presence of fire-adapted species need not condemn us to another million years of regular burning ("cave man forestry" in the words of a friend) unless we let it. If our goal is a well-functioning carbon cycle, with carbon held out of the air for long periods, with abundant decay organisms, then we can experiment with ways out of this trap.

Good soil is alive. The carbon cycle depends on life. Burning it up isn't good.

Peter --

Excellent response, helpful sources! Thank you.

Thank you for bringing that topic to the public attention. I heard earlier about Allan Savorya theory that while livestock are one of the main part of the climate change problem, but that they also can be the part of the solution to that problem, but unfortunately I didn't understood the whole idea back then... Now thanks to you, I get it, and I definitely agree with Glenn Gal, some of numbers he is using in his speech are kind of strange if not say more but still he is definitely mostly right ...
Again, huge thanks for that post !
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"What is wanted is not the will to believe, but the will to find out, which is the exact opposite."-- Bertrand Russell, Skeptical Essays (1928)