photo Memories of the Dust Bowl      Pinterest  90deffe52297bcda9b2cfa8277288516  

The  seventh   essay in a series on how American agriculture can  thrive in  a strenuous good-faith effort to halt global warming.  The  first six,   earliest first, are these:

1.   What-is-a-carbon-footprint 

2.    Comparing-carbon-footprints-of-world-and-american-agriculture  

3.    Fossil-fuels-in-the-carbon-footprint-of-american-agriculture  

4.  Carbon-tax-and-american-agriculture  

5.  Carbon foodprints in American Agriculture

6.  Carbon sequestration and storage in soil 

Abstract:  A rising “carbon fee” would  be  un-affordable  to many agriculturalists whose small businesses would get no dividend  from “carbon fee and dividend (CFD)”  as households would; so, most farmers and ranchers  oppose CFD,  though deeply concerned about the effects of weather volatility on farming today and in the future.   Moreover, the decrease in carbon dioxide emissions from American agriculture expected from a rising carbon tax would be paltry compared to the drop expected in all other sectors of the economy, not worth the harm to farmers.  Carbon sequestration and storage in soil (CSSS), however, would benefit agriculturalists and the whole population enormously more than simply reducing CO2 emissions from agriculture. The potential gains from  CSSS in improved soil and atmosphere health should make it an integral part of the CCL exemplar for CFD.  The best path to that,  fair and sensible,  would earmark some of the annual carbon  fee revenues for  direct payments to farmers and ranchers who actively sequester and store carbon.          

           The objective  of  Carbon Fee and Dividend (CFD)  is to  rapidly shrink the US carbon footprint,  which  for 2015 was about   6,703 M mt  CO2-e/yr,   82% CO2  itself.  (Graph 7.1)  Most of the CO2 came from fossil fuel combustion (FFC).

 Graph 7.1.  Carbon footprint of USA ca. 2015 in million metric tons CO2-e/yr of three major GHGs, by gas: CO2 vs CH4 and N2O together.  Data sources see earlier  essay in this series

            The blue carbon dioxide block in Graph 7.1 is the main target of a carbon tax or fee on coal, oil and gas  collected “upstream.”  The fee will  have its biggest effect on  CO2 emissions from FFC,  with  much less leverage on methane and nitrous  oxide, the two other major greenhouse gases (GHGs).  

            A tax that causes a 50% decrease in FFC should bring (roughly) a 50% fall   in CO2 emissions. Graph 7.2 shows how the US carbon footprint might look in two hypothetical future scenarios.  With FFC down 50%,  the three-GHG footprint is down 40%.  With  FFC down 80%, the footprint has shrunk by 2/3.  If  CO2 emissions went to zero (not shown), the overall footprint would  be 82% smaller but could not shrink further,  as the releases  of CH4 and N2O  are not governed by FFC.  [Actually, they are, but less   than CO2 emissions.]  

 Graph 7.2 The US carbon footprint in two hypothetical future scenarios of less fossil fuel combustion compared to current.  Units and sources as for Graph 7.1

            The overall carbon footprint of the country should  shrink in step with falling FFC.   The footprint of  agriculture, however, will not show the same effect.  Even though the Ag sector relies on FFC,  the makeup of this sector’s carbon footprint is very different from that of the rest of the economy. Graph 7.3 (below) profiles the  two sectors, Ag (677 M mt CO2-e/yr) and not-Ag (6026 M mt CO2-e/yr).  For Ag, CO2 is only 23% of the sector total; for the rest of the economy, CO2 is 88%.  A 50% cut in FFC for the Ag sector will reduce the three-GHG carbon footprint by just 78 M mt (-12%) while a 50% cut of  FFC in all other sectors would bring down total emissions by 44%  or  2,670 M mt CO2-e,  a 34-fold absolute difference from Agriculture.



Graph 7.3  Carbon footprint by gas and sector, USA ca 2015

            Agriculture must  reduce  FFC, no question.  Putting the same carbon tax pressure on this sector  as on all others,  however, is inefficient and harmful.  It delivers less gain in total GHG reductions for  more pain to farmers and ranchers,  who  must incur new expenses to lower use of  fossil fuels.  Dividends from CFD  to households that are not businesses will never begin to cover costs of  responding to  the carbon fee to  which a  farm household that is a business is exposed.

                Fortunately, farming and ranching are uniquely positioned to make hay out of the country’s emergent need to  radically cut  emissions of  CO2  and  get it out of  the atmosphere.    Carbon sequestration  and storage in soil (CSSS) removes carbon from the atmosphere.  It also also improves soil’s fertility and resilience to weather volatility.  With legumes planted,  it can overcome the current dependence (some say addiction)  to synthetic nitrogen fertilizers and biocides. By  low-tech changes in management such as cover crops, no-till seeding and improved grazing of grasslands,  agriculture could come close to being carbon neutral (i.e. 3-gas footprint near zero, net of emissions minus sequestrations).  Only farmers and ranchers can do large-scale CSSS.

            Does this sound too good to be true?  The benefits of getting carbon back into soil and keeping it there are incontestable.   There are of course questions about how much carbon can be sequestered and stored on US agricultural lands and on those of the whole world.  Graph 7.4 uses a middle of the road estimate  for a “maximal”  rate of sequestration per acre   to project how much carbon dioxide could be sequestered  on the 2/3 of  US agricultural acreage that is grassland/pasture/rangeland.  (See p. 61 of this report by Garnett et al.) The highest rate shown (0.68 metric tons of CO2/acre applied by improved management to 840 million acres could sequester 571 M mt CO2/yr,  about 84% of the 2015 agricultural 3-GHG footprint.  Lower rates on fewer acres could sequester less, but half that rate on half those acres could sequester 143 M mt CO2/yr,   more than the  121 M mt CO2/yr  emitted from the whole Ag sector. 

            Graph 7.4 gives a  conservative picture.  It does not cover another 400 million acres of cropland that could also be used intensively for CSSS, at sequestration rates/acre higher than those averaged on properly-grazed grassland.



Graph 7.4  Potential for CO2 sequestration in M mt/yr by sequestration rate/acre and acreage managed with improved grazing on US grass and pasture lands

            The potential for large scale carbon sequestration, though unproven, appeals strongly to ecologists and agriculturalists,.   CSSS would not be a complete solution to  global warming even if every acre of now  or formerly agricultural land in the  world could take in and store carbon at the  highest rates in peer-reviewed literature.  It  is a wondrous  strategy for the world’s ranchers and farmers to deploy in lowering GHG emissions and removing CO2 from the air.  It  is not a free lunch but it’s a bargain.

             As I’ve explained in earlier essays, adopting even  low-tech methods for switching from conventional to “regenerative” agriculture will for several years cost everyone who hasn’t already done  it  money  and  labor  that many just don’t have.  Distaste for  being forced into an investment that one can’t afford makes many ranchers and farmers oppose CFD,  dooming it legislatively.  Citizens Climate Lobby is the  the outstanding nonprofit organization that has proposed  a CFD plan to legislators for their consideration.  I and like-minded colleagues  entreat  CCL   to revise the plan, allocating some revenues from CFD  to directly help farmers and ranchers commit to  CCCS.      

                 An analogy from chemistry is apt.  In graph 7.5 below, the orange line is the curve of  the “activation energy” to get US farmers and ranchers rolling on CSSS. We believe the curve is too steep and too high to be surmounted if the only impetus to get over the top  is the prod of the rising carbon fee on  fossil fuels used by farmers and ranchers.  The blue line represents a catalyzed reaction, where the catalyst is money from the carbon fee revenues.  I think the choice is clear.

Graph 7.5  Schematic of  activation energy curve for an un-catalyzed (orange line) reaction and the same reaction catalyzed (blue line).

Carbon Sequestration and Storage in Soil

by Stephen Shafer on December 30, 2017

Carbon  Sequestration and Storage  in Soil


3e5d8c05f2c45a864f2d39a1bb7afc9d--th-grade-science-gcse-science                                                                        image courtesy of www.fibershed.com


The  sixth  essay in a series on how American agriculture can  thrive in  a strenuous good-faith effort to halt global warming.  The  first five,   earliest first, are these:

1.   What-is-a-carbon-footprint 

2.    Comparing-carbon-footprints-of-world-and-american-agriculture  

3.    Fossil-fuels-in-the-carbon-footprint-of-american-agriculture  

4.  Carbon-tax-and-american-agriculture  

5.  Carbon foodprints in American Agriculture

Abstract: There is now wide agreement that stemming future global warming will require not only decreasing emissions of greenhouse gases but also removing carbon dioxide from the atmosphere.   Carbon sequestration and storage in soil ( CSSS) offers a  way to do that draw-down  while improving  soil health  to the benefit of farmers, ranchers and the nation’s people.    This essay asks whether  large-scale CSSS by agriculture can be a partial solution to global warming.  The conclusion is “yes,” as long as it is not pushed as a cure-all or regarded as a fast-acting antidote to the fiscal strain that a carbon tax would put on farmers.

          Over the last twelve thousand years   the world’s agricultural soils have been degraded  by  loss of  once-abundant carbon.   Their productivity has been propped  up by synthetic nitrogen fertilizers and tapping finite resources.  They are thus primed to  draw large amounts of  carbon  from the atmosphere as carbon dioxide  and  where undisturbed  keep it indefinitely as carbon sequestered and stored in soil.  Appendix 1 in the Read More section that begins further down  explains the  mechanisms of  CSSS pictured in the cartoon heading to this essay.

              Carbon sequestration and storage in soil (CSSS) can improve most aspects of soil health affected  by  post-1800  agriculture while removing carbon dioxide from an atmosphere overloaded with it.  It looks a way  by which agriculture can at  relatively low cost  improve the quality of the  soil, water and air resources on which the enterprise depends while significantly decreasing its net emissions of greenhouse gases. 

            Many advocates  of a  Carbon Fee and Dividend  plan  believe the medium and long term  benefits of  widely implementing CSSS  in the USA will easily outweigh the short-term costs to farmers and ranchers of the transition from current typical practices to CSSS.  As an environmentalist and farmer,  I disagree.  CSSS, despite  its merits, is not a perfect antidote for all farmers and ranchers for the  hit  that a carbon tax would make on this community

            How much carbon could American agricultural  soils draw down and hold?  If greenhouse gas releases releases are  600-700 million metric tons (M mt) of CO2-equivalent per year, capacity for CSSS  should  be a healthy fraction of that.        Determinants of what can be achieved are well-laid out in the diagram below from a worksheet by Jennifer Carson, University of  Western Australia.  Management is important  in how much of the attainable will be reached.  It need not be by humans; the grazing patterns of wild hard-hoofed mammals (bison, elephant, antelope)  were  a form of management.


           A crucial one of the several factors in  “potential OC [organic carbon]” is soil organic carbon content.    Carbon-depleted US and world agricultural soils are hungry for the element.   Calculating  average attainable  capacity/acre  for the world, however,  is  imprecise.

            In a 2007 article Lal, Follett and colleagues  reckon (with large margin of error) the actual amount of carbon that could be sequestered in American soils and woodlands combined, arriving at a point estimate of 288 million metric tons carbon/year (Mt C/yr); I get  from Tables 5 and 6 of the article that improved practices on cropland could sequester 54.7 to 164.2 Mt C/yr (mid-range value 109.4 Mt C/yr). Improved practices on pasture and rangeland could sequester 16-50.4 Mt C/yr (mid-range value 33.2 Mt C/yr).  Summing these two returns 142.6  Mt C/yr for cropland + pasture + rangeland,    only half of 288 Mt C/yr. The difference comes mainly from  not  counting forestlands. 

           Suppose USA agricultural lands could sequester 140 million metric tons (M mt) of carbon/year.   How would that compare to annual GHG emissions from US agriculture of  (say)  650 million metric tons CO2-e?  140 M mt C equates to 518 M mt CO2, since CO2 is only 27% carbon by mass.  Even if CSSS  locked away only  half of  140  M mt C,  that would be a substantial withholding from the releases to the atmosphere.  

            The abstract of the 2007 article by Lal and colleagues  is excerpted in Appendix 2 in the Read More section.  The article is not the last word on the efficacy of  CSSS.  Reservations  about ultimate 100% success, however,  did  not keep Lal and colleagues from calling urgently in 2007  for CSSS [and in forests].  They  should not keep anyone from renewing that call more emergently in 2018.

            More enthusiasm and fewer reservations about CSSS on grasslands come from disciples of Allan Savory’s “holistic grazing management” for regenerative agriculture. I think this is right in principle.  Whether Savory’s ideas  applied can improve > 800 million acres of variegated American grasslands while storing  millions of  tonnes  of carbon  is an unanswered question.  His  adherents use before-and- after photos and personal testimony to make their cases about small and medium-scale improvements; this does not sit well with  academic range scientists who have closed ranks against Holistic Management on the grounds that it is not based on sound data.  Appendix 3  in the Read More section gives more space to the arguments.

            Even those who side  with  Savory on principle should never  pretend that holistic management of grazing and crops causing CSSS is a full solution to global warming.  At best,  it  is a constructive step in the medium and long term to the world and its farmers,  unusual  in being a positive sum game.  Better yet,  it offers  a sustainable seat at the table  for  livestock raisers,  who are  often viewed by climate advocates  as adversaries. 

           A  report from the Food Climate Research Network (Garnett et al 2017)  is respectful but cautious about what we should expect from CSSS. A line on page 64 makes a good coda to this essay:  “Notably too, all the peer-reviewed studies fall below 4 t CO2/ha/yr, with a mean of about 1.8 t CO2 /ha/yr (or 0.5 t C/ha/yr). As Section 3.5.3 below will discuss, in the grand scheme of things this potential, while useful, is modest.” [emphasis added]

Read More section starts below here with three appendices.

  [click to continue…]

Carbon Foodprints in American Agriculture

December 17, 2017

                                                                        photo “Corn Harvest”  from pixabay,com This is the fifth essay in a series on how American agriculture can  thrive in  a strenuous good-faith effort to halt global warming.  The  first four,   earliest first: 1.   What-is-a-carbon-footprint  2.    Comparing-carbon-footprints-of-world-and-american-agriculture   3.    Fossil-fuels-in-the-carbon-footprint-of-american-ag   4.  Carbon-tax-and-american-agriculture   Abstract   I [...]

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Carbon tax and American Agriculture

December 14, 2017

The Keeling Curve:   Atmospheric CO2 at Mauna Loa Observatory,  annual peak and  trough by year 1960 to now  Source Scripps Institute This is the fourth of a series of essays about American agriculture and climate change.  The first three, in order of appearance are these:   1.   what-is-a-carbon-footprint 2.    comparing-carbon-footprints-of-world-and-american-agriculture 3.   Fossil [...]

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Fossil Fuels in the Carbon Footprint of American Ag

December 6, 2017

                                                                                                                                                                                                                          photo from Free Farm Images The  third  essay in a series on how American agriculture can  thrive in  a strenuous good-faith effort to halt global warming.  The  six,   earliest first, are these: 1.   What-is-a-carbon-footprint  2.    Comparing-carbon-footprints-of-world-and-american-agriculture   3.    Fossil-fuels-in-the-carbon-footprint-of-american-agriculture   4.  Carbon-tax-and-american-agriculture   5.  Carbon foodprints in American Agriculture 6. Carbon sequestration and [...]

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Comparing carbon footprints of world and American agriculture

December 2, 2017

              June grazing: photo by Stephen Shafer    Abstract In the  world, and in the USA, crop and livestock agriculture  accounts for about 10% of total greenhouse gas emissions.  In both spheres, fossil fuel combustion (FFC)    is usually tagged with only  9-12% of agricultural GHG releases.  Ag-related sources not [...]

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What is a Carbon Footprint

December 2, 2017

  Part 1.  What is a “carbon footprint”  and how do we use it?   First in the series,  directly below    Part 2.  Comparing the carbon footprints  of world and American agriculture.       Part 3.  Fossil Fuels  in the Carbon Footprint of American Agriculture  Part 4.   Carbon Tax  Part 5.  Carbon foodprints in American agriculture [...]

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Sue Stewart

May 2, 2016

                                                                  Sue Stewart died March 13, 2016  after  a long illness.  Sue was a good friend to us, to children, and to all animals in her care,  as well as being a devoted wife to Graeme.       We remember her joy in taking care of animals, whether working at Rhinebeck Animal Hospital, as [...]

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Breeding 2013 and lambing 2014

April 20, 2014

     Lambing 2014 as of 4/20/14 .   First live birth Feb 1. last March 21.  More lambs born here (105) than ever before.    57 ewes put to rams last fall.   Three sold at NYS Bred Ewe and Ewe Lamb Sale in October, of which two had twins and one triplets.    Of [...]

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