Soils

Soils now contain perhaps 3 times as much carbon as either the atmosphere or above-ground biomass.

Ranching and farming can both move very large amounts of carbon from the air into soils - IF done right.

'Total Decarbonization' of US Economy Would Create 25 Million Jobs 0820.rtf

     The picture is from a piece of land in Africa, the Karoo.  Holistic Management grazing is used to the left of the fence, as locals use methods taught by the Savory Institute.  Traditional modern grazing methods are used to the viewer’s right.

    Holistic Management involves grazing cattle (or buffalo, caribou, etc.) for short (~ 1 week) periods on a patch of land, then moving them to another patch.  (Sheep, and especially goats, should not be used, as they crop the grass too short.)  After several months of moving to one patch after another, they return to the original patch, then revisiting each patch in turn.  In the meantime, dung beetles move carbon (in dung) underground, while close-cropped perennial grass adds to its roots and sends up new shoots (as it does after a lawn is mowed).  The cattle hooves help break up the soil, so moisture and seeds can penetrate.  The soil stores more carbon in fungal networks, much of it in the form of glomalin.  The soil carbon results in soils soaking up 75-95% of rainfall, instead of 5-25% of rainfall in soils not treated (to viewer’s right of the fence.)

     This practice removes carbon from the air and stores it soil.  Moreover, the soil becomes a much better sponge for holding water.  A few of the articles (and 1 PPT) below address this practice and its results.

Allan Savory's TED talk, is shown below

This may be our most important way to reduce CO2 levels in the air.

     Estimates vary for how much carbon our soils can remove from the air, and how fast.  In 2001, US Department of Agriculture staff estimated (see below) that US farming and ranching practices move 20 million tons of carbon a year from air to soils, for $6 per ton of CO2 removed initially.  They also estimated that removal could be increased to 10 times as much, more than 10% of US carbon emissions, largely via changes in tilling practices (no-till, etc.)

Allan Savory Says Says More Cows on the Land Will Reverse Climate Change. Science Says Otherwise. 0217.rtf

Partly, the article debunks a straw man: increased cattle per acre, but without fast rotation.  Good points - When you take cattle off the land to sell for meat, the land loses the nutrients on the hoof.  Replication has not been done.  Also, fallow (ungrazed) land recovers, eventually.  Also, cattle did not co-evolve with the driest rangelands.  Savory’s claims about how much CO2 can be removed may well be overblown, especially net of cows’ CH4 emissions.

Holistic Management Can Save Our Soils and Reduce CO2 Levels 0913 - For more detail, see study below.

Restoring Soil Carbon to Slow Climate Change - Savory 0413.pdf 20 pp
    Holistic Management practices can move 2.5 tonnes of carbon / hectare / year (= 1 ton / acre / year = 0.25 kg / square meter [sq m]) from the air to soils, maybe more, building soil in the process.  This would increase removal almost by another factor of 10, from USDA's 2001 estimates.  Applied to 4 billion hectares of degraded grasslands (rangelands) around the world (about 20% of Earth's land), this would move 10 billion tons (GT) of carbon from air to soils.  Changed grazing practices would do it, rather than changed tillage ones.  10 GT / year removal ~ current world carbon emissions.  The atmosphere holds almost 1,000 GT of CO2.  Thus, Holistic Management applied to the max could cut atmospheric CO2 levels by ~ 4 ppm / year, if we reduce our emissions to zero.
    For perspective, the top foot of 1 square meter of soil weighs 350-500 kg.  Typically, 1% to 12% of that is organic carbon.  So, soils (except deserts, see map at top of page) contain 4 to 60 kg of carbon / sq m.  That includes 8-20 in most of the US, Canada, Russia, Siberia, Europe and China.  That's less than permafrost soils, but more than most tropical rainforests.  In all, Holistic Management practices might increase soil carbon by 1-6% / year (& topsoil mass by 0.05% / year), while tillage changes can increase soil carbon 0.1-0.6% / year.

     However, soil microbes respire carbon to the air faster as soil warms.  This counters moving carbon from air to soils.

Holistic Management: Move Carbon Back to Soil - Jim Laurie 0408 - PPT
    Extract 2 ppm (10 GigaTons of CO2) / year from the air by proper grazing on some 10 million square miles of rangeland.  That's half a ton of carbon / acre (1.1 tonnes of carbon / hectare) / year.  It would take 1-2 centuries to double the carbon content of treated soils.  In all, goes the plan, extract 80 ppm of CO2 from the air and return it to soils.  Pass 350 ppm on the way down, via 10 GT CO2 / year moved to soils, by planned fast rotation grazing on marginal lands.  Decrease ocean dead zones, avoiding Canfield Ocean [very hot, anoxic, sulfur dominated] and a repeat of Permian Extinction.

     Allan Savory, founder of the Holistic Management Institute (which advocates fast (~ 1 week per pasture) rotation grazing on rangelands), says that a 0.5% increase in soil carbon in the world's degraded lands would remove 150 gigatonnes of carbon from the air.  That's 15 years of human emissions at current rates.

Section Map: Reversing Climate Change