Home > Huge Carbon Debt vs Carbon Credit, intergenerational equity & global justice

Huge Carbon Debt vs Carbon Credit, intergenerational equity & global justice

by Dr Gideon Polya - Open-Publishing - Sunday 29 September 2013

The myth of neoliberalism claims trickle down benefits for the masses from maximizing freedom of the smart and advantaged to exploit natural resources. The neoliberals ignore the worsening problem of Carbon Debt due to pollution of the world’s one common atmosphere with CO2 that can now be estimated at a value of $127 trillion or roughly 2 years of global GDP.

Top climate scientists and biologists say that a safe and sustainable existence for all peoples and all species on our warming-threatened Planet requires a relatively rapid reduction of atmospheric carbon dioxide (CO2) concentration to about 300 parts per million (300 ppm) from the current level of about 400 ppm CO2. 300 ppm CO2 had not been exceeded for about 1 million years until after the onset of the Industrial Revolution and what is now called the Anthropocene Era in view of the massive concomitant mass extinction of species, the species extinction rate now being 100-1,000 times above normal [1, 2].

Repayment of this enormous Carbon Debt requires a rapid switch to the best non-carbon and renewable energy (solar, wind, geothermal, wave, tide and hydro options that are currently roughly the same market price as coal burning-based power) and to energy efficiency, public transport, needs-based production, re-afforestation and return of carbon as biochar to soils and oxygen-free underground storage coupled with correspondingly rapid cessation of fossil fuel burning, deforestation, methanogenic livestock production and population growth. However simple removal of CO2 from the atmosphere to circa 300 ppm CO2 is insufficient because a huge amount of CO2 has ended up in the oceans.

Thus Long Cao and Ken Caldeira (Stanford University) (2010): “Carbon capture from ambient air has been proposed as a mitigation strategy to counteract anthropogenic climate change. We use an Earth system model to investigate the response of the coupled climate–carbon system to an instantaneous removal of all anthropogenic CO2 from the atmosphere. In our extreme and idealized simulations, anthropogenic CO2 emissions are halted and all anthropogenic CO2 is removed from the atmosphere at year 2050 under the IPCC A2 CO2 emission scenario when the model-simulated atmospheric CO2 reaches 511 ppm and surface temperature reaches 1.8 ◦C above the pre-industrial level. In our simulations a one-time removal of all anthropogenic CO2 in the atmosphere reduces surface air temperature by 0.8 ◦C within a few years, but 1 ◦C surface warming above pre-industrial levels lasts for several centuries. In other words, a one-time removal of 100% excess CO2 from the atmosphere offsets less than 50% of the warming experienced at the time of removal. To maintain atmospheric CO2 and temperature at low levels, not only does anthropogenic CO2 in the atmosphere need to be removed, but anthropogenic CO2 stored in the ocean and land needs to be removed as well when it outgasses to the atmosphere. In our simulation to maintain atmospheric CO2 concentrations at pre-industrial levels for centuries, an additional amount of CO2 equal to the original CO2 captured would need to be removed over the subsequent 80 years” [3].

Various methods have been proposed for removing atmospheric CO2 from past or continuing pollution including (with critiques in parenthesis):

(a) Carbon Capture and Storage or Carbon Capture and Sequestration (CCS) underground of CO2 from power stations ( widely touted but not presently commercially feasible [4]);

(b) similar storage of power station-derived CO2 in the deep ocean (similarly costly in relation to compression and also contraindicated by associated ocean acidification deadly to calcifying photosynthetic and animal organisms with calcium carbonate-based exteriors e.g. coccolithophore algae, corals, foraminifera, echinoderms, crustaceans and molluscs);

(c) use to generate biomass through photosynthesis in associated algal ponds (huge expense and incomplete CO2 removal );

(d) fertilization of oceans to promote photosynthetic fixation of CO2 into biomass (huge cost and massive global ecosystem disruption with unknown consequences);

(e) biological removal of CO2 as cellulose in tree trunks and as carbon compounds in the soil (clearly a major part of the solution but there are limits to re-afforestation and soil carbon storage; there is presently about 700 Gt C in biomass (mostly wood) and 1,600 Gt C in soil as humus; SE Australian Eucalyptus regnans forests are the best forest carbon sinks in the world);

(f) relatively cheap CO2 sequestration as bicarbonate in oceans through Accelerated Weathering of Limestone (AWL) by scrubbing power plant emissions in sea water plus limestone (CaCO3) (compression costs would make more general application to removing CO2 from the atmosphere even more expensive – however in the context of a presently existing and unfortunately entrenched and dominant carbon economy this mechanism is important ); and

(g) biochar (carbon, charcoal) production and storage through anaerobic pyrolysis at 400-700C of waste biomass cellulosic materials - the annual biochar production using existing agricultural and forestry waste would be similar to the amount of carbon pollution produced annually by industry.

The latter 2 mechanisms are amplified below.

(1) Accelerated Weathering of Limestone (AWL).

The waste gas from burning coal or gas is passed through a sea water-limestone (CaCO3) scrubber with the following reaction: CO2 (gas) + CaCO3 (solid) + H2O <-> Ca2+ (aqueous) + 2 HCO3- (aqueous) . The scrubbing solution is then piped to the sea. Carbon in the oceans as bicarbonate is 10 times that in all recoverable fossil fuel reserves and about 60 times that in the CO2 in the atmosphere. The carbon in carbonate minerals is about 4,000 times greater than the carbon in oil and coal fossil fuel reserves and the AWL process would in part reverse the deleterious acidification the oceans due to the massive CO2 pollution of the atmosphere [5, 6].

Dr G.H. Rau (Institute of Marine Sciences, University of California, Santa Cruz, and Carbon Management Program, Lawrence Livermore National Laboratory) (2011): “A lab-scale seawater/mineral carbonate gas scrubber was found to remove up to 97% of CO2 in a simulated flue gas stream at ambient temperature and pressure, with a large fraction of this carbon ultimately converted to dissolved calcium bicarbonate. After full equilibration with air, up to 85% of the captured carbon was retained in solution, that is, it did not degas or precipitate. Thus, above-ground CO2 hydration and mineral carbonate scrubbing may provide a relatively simple point-source CO2 capture and storage scheme at coastal locations. Such low-tech CO2 mitigation could be especially relevant for retrofitting to existing power plants and for deployment in the developing world, the primary source of future CO2 emissions. Addition of the resulting alkaline solution to the ocean may benefit marine ecosystems that are currently threatened by acidification, while also allowing the utilization of the vast potential of the sea to safely sequester anthropogenic carbon. This approach in essence hastens Nature’s own very effective but slow CO2 mitigation process; carbonate mineral weathering is a major consumer of excess atmospheric CO2 and ocean acidity on geologic times scales” [7].

For minimum cost, this method would require ready access to limestone (CaCO3) and the sea and application to the waste gas from fossil fuel combustion in power stations, noting that ideally the world will shift to 100% renewable energy as soon as possible [8-10]. Estimated costs depending closeness to sea water and limestone range up to $40 per tonne CO2 sequestered as ocean bicarbonate [11] . However this route, while a potentially valuable mechanism for CO2 reduction in the context of an existing mainly carbon burning -based economy, would be much more expensive due to compression costs if applied to atmospheric CO2 in general.

(2). Biochar.

Biochar is a major element of required actions to draw down atmospheric CO2 concentration to a safe and sustainable level of about 300 ppm, as perceived by top US climate scientist Professor James Hansen and his colleagues: “Carbon sequestration in soil also has significant potential. Biochar, produced in pyrolysis of residues from crops, forestry, and animal wastes, can be used to restore soil fertility while storing carbon from centuries to millennia . Biochar helps soil retain nutrients and fertilizers, reducing emissions of GHGs such as N2O. Replacing slash-and-burn agriculture with slash-and-char and use of agricultural and forestry wastes for biochar production could provide a CO2 drawdown of 8 ppm in half a century.” [12].

Atmospheric CO2 can be reduced from the current 400 ppm CO2 back to a safe and sustainable 300 ppm CO2 by fixing CO2 as cellulose via solar-energy-driven photosynthesis (nCO2 + nH2O -> (CH2O)n + O2 ) with subsequent anaerobic pyrolysis of cellulosic material (e.g. waste wood and straw) to yield carbon (C, charcoal) ((CH2O)n -> nC + n H2O).which can then be added to soil or buried in holes in the ground (e.g. in used coal mines).

Thus p224, Progress in Thermochemical Biomass Conversion, volume 1, IAE Bioenergy, ed. A. V. Bridgewater (Blackwell Science) informs us that we could obtain 1.7 Gt C/yr (straw from agriculture) + 4.2 Gt C/yr (total grass upgrowth from grasslands upgrowth) + 6 Gt C/yr (possible sustainable wood harvest) = 11.9 Gt C/yr [13, 14]. From this one can see why biochar expert Professor Johannes Lehmann of Cornell University is correct in calculating that it is realistically possible to fix 9.5 billion tonnes of carbon per year using biochar, noting that global annual production of carbon from fossil fuels is about 9 billlion tonnes [15-17].

(3) Carbon Debt and biochar.

There is about 700-750 Gt C in the atmosphere (mostly as 750 x 3.7 = 2775 Gt CO2; half due to historical fossil fuel combustion); 700 Gt C in biomass (mostly wood); 1,600 Gt C in soil; 36,000 Gt C in ocean as bicarbonate ion (HCO3-); and no net CO2 from vulcanism and weathering (time scale < 100,000 years) [18, 19].

A biochar-based return to the pre-Industrial Revolution atmospheric level of 280 ppm CO2 would mean removing about half the atmospheric CO2 i.e. 2,775 Gt CO2/2 = 1,388 Gt CO2 ( = 1,388 / 3.7 = 375 Gt C ) as biochar at a maximum rate of about 12 Gt C per year i.e. taking about 30 years.

The cost of conversion of cellulosic waste to biochar in the US mid-West is about $49-$74 per tonne CO2 as compared to $210-$303 per tonne CO2 in the UK [20]. Removing 1,388 Gt CO2 as biochar at a cost of about $100 per tonne CO2 = $138, 800 billion = $139 trillion or about 2 years of global GDP.

The annual Carbon Debt of various key countries in terms of the cost of removal of CO2 as biochar is set out below.

(A). The GDP of some key countries in descending order of GDP (IMF data) was $71.7 trillion (the World), $16.6 trillion (EU), $15.7 trillion (US), $8.23 trillion (China), $6.00 trillion (Japan), $3.40 trillion (Germany), $2.61 trillion (France), $2.44 trillion (UK), $2.40 trillion (Brazil), $2.02 trillion (Russia) $2.01 trillion (Italy), $1.82 trillion (India), $1.82 trillion (Canada), $1.54 trillion (Australia), $0.88 trillion (Indonesia), $0.38 trillion (South Africa), $0.27 trillion (Nigeria), $0.23 trillion (Pakistan), and $0.15 trillion (Bangladesh) [21].

(B), The populations of these key countries in millions (circa 2013) are 7,113.7 (the World), 739.2 (EU), 316.7 (US), 1,360.1 (China), 127.3 (Japan), 80.5 (Germany), 65.7 (France), 63.7 (UK), 201.0 (Brazil), 143.5 (Russia), 59.7 (Italy), 1,234.4 (India), 35.2 (Canada), 23.2 (Australia), 237.6 (Indonesia), 53.0 (South Africa), 173.6 (Nigeria), 184.3 (Pakistan), and 152.5 (Bangladesh) [22].

The annual global GHG pollution has been revised by World Bank experts up from 41.8 Gt CO2-e to 63.8 Gt CO2-e., this revision taking into account a Global Warming Potential of 72 for methane on a 20 year timeframe (while actually 105 on this time frame taking aerosol effects into account as compared to 21 on a 100 year time frame) and reconsideration of livestock impacts including livestock-related land use [23]. For consistency of data, we will take the lower figure in (C) below.

(C). The annual GHG pollution for various countries in billion tonnes (Gt) CO2-e (2005; land use included) are: 41.80 (the World), 5.33 (EU), 6.93 (US), 7.23 (China), 1.39 (Japan), 1.01 (Germany), 0.58 (France), 0.68 (UK), 2.85 (Brazil), 2.01 (Russia), 0.58 (Italy), 1.88 (India), 0.81 (Canada), 0.57 (Australia), 2.04 (Indonesia), 0.43 (South Africa), 0.45 (Nigeria), 0.24 (Pakistan), 0.14 (Bangladesh) [24].


(D). The annual per capita GHG pollution of these countries
using the above data is accordingly roughly (in units of tonnes CO2-e per person per year) 5.9 (the World), 7.2 (EU), 21.9 (US), 5.3 (China), 10.9 (Japan), 12.5 (Germany), 8.8 (France), 10.7 (UK), 14.2 (Brazil), 14.0 (Russia), 9.7 (Italy), 1.5 (India), 23.0 (Canada), 24.6 (Australia), 8.6 (Indonesia), 8.1 (South Africa), 2.6 (Nigeria), 1.3 (Pakistan), and 0.9 (Bangladesh).

Assuming a cost of about $100 per tonne CO2 converted to biochar, one can accordingly calculate the annual Carbon Debt being run up by our set of key countries.

(E). The annual Carbon Debt on the basis of biochar-based CO2 sequestration at $100 per tonne CO2 is $4,180 billion (the World), $533 billion (EU), $693 billion (US), $723 billion (China), $139 billion (Japan), $101 billion (Germany), $58 billion (France), $68 billion (UK), $285 billion (Brazil), $201 billion (Russia), $58 billion (Italy), $188 billion (India), $81 billion (Canada), $57 billion (Australia), $204 billion (Indonesia), $43 billion (South Africa), $45 billion (Nigeria), $24 billion (Pakistan), and $14 billion (Bangladesh).

(F) The annual Carbon Debt as a percentage of country or region GDP is accordingly 5.8% (the World), 3.2% (EU), 4.4% (US), 8.8% (China), 2.3% (Japan), 3.0% (Germany), 2.2% billion (France), 2.8% (UK), 11.9% (Brazil), 10.0% (Russia), 2.9% (Italy), 10.3% (India), 4.5% (Canada), 3.7% (Australia), 23.2% (Indonesia), 11.3% (South Africa), 16.7% (Nigeria), 10.4% (Pakistan), and 9.3% (Bangladesh).

(G). The per capita annual Carbon Debt on the basis of biochar-based CO2 sequestration is $588 (the World), $721 (EU), $2,188 (US), $532 (China), $1,092 (Japan), $1,255 (Germany), $883 (France), $1,068 (UK), $1,418 (Brazil), $1,401 (Russia), $972 (Italy), $152 (India), $2,301 (Canada), $2,457 (Australia), $859 (Indonesia), $811 (South Africa), $259 (Nigeria), $130 (Pakistan), and $92 (Bangladesh).

The historical Carbon Debt for all countries in the world can also be roughly determined. Thus in a 2008 letter to Australian PM Kevin Rudd, NASA’s Dr James Hansen provided data on country and region percentage responsibility for 346 Gt C (1,270 Gt CO2) fossil fuel-derived CO2 pollution between 1751 and 2006 [25]:

(H), The historical Carbon Debt for key countries (1750-2006) has been expressed in US dollars at $100 per tonne CO2 sequestered as biochar: $127.000 trillion (the World), $40.480 trillion (EU), $36.377 trillion (US), $10.845 trillion (China), $5.156 trillion (Japan), $8.731 trillion (Germany); $3.369 trillion (France), $7.938 trillion (UK), $1.041 trillion (Brazil), $9.788 trillion (Russia), $3.196 trillion (Italy), $3.307 trillion (India), $2.052 trillion (Canada), $2.052 trillion (Australia), $1.241 trillion (Indonesia), $0.272 trillion (South Africa), $0.896 trillion (Nigeria), $0.943 trillion (Pakistan), and $0.813 trillion (Bangladesh) [26].

(I) Per capita historical Carbon Debt for our key countries is as follows: $17,853 (the World), $54,762 (EU), $114,863 (US), $7,974 (China), $40,503 (Japan), $108,460 (Germany); $51,279 (France), $124,615 (UK), $5,179 (Brazil), $68,209 (Russia), $53,534 (Italy), $2,679 (India), $58,295 (Canada), $88,448 (Australia), $5,223 (Indonesia), $5,132 (South Africa), $5,161 (Nigeria), $5,116 (Pakistan), and $5,331 (Bangladesh).

However if one assumes that a return to 300 ppm is unattainable (I certainly do not) then one should consider the estimate of the WBGU (that advises the German Government on climate change) that for a 75% chance of avoiding a 2C temperature rise the world can emit no more than 600 Gt CO2 between 2010 and zero emissions in 2050. Each country would thus have a notional “share” of this terminal GHG pollution “budget” and from current pollution data one can calculate on a per capita basis the remaining Carbon Credit expressed in terms of biochar-based cost of CO2 removal. This has been done by multiplying estimates of “years left” at current rates by the permitted average of about 2.1 tonnes CO2 per person per year [26, 27].

(J). Per capita Carbon Credit expressed in US dollars at $100 per tonne CO2 sequesterable as biochar: $7,800 (the World), $949 (EU), $21 (US), $3,268 (China), $780 (Japan), $611 (Germany), $1,118 (France), $759 (UK), $548 (Brazil), $485 (Russia), $1,102 (Italy), $7,823 (India), $0.0 (Canada), minus $127 (Australia), $380 (Indonesia), $843 (South Africa), $3,964 (Nigeria), $5,967 (Pakistan), and $16,257 (Bangladesh). Note that Australia and Canada have already used up their “fair shares” and are now stealing the entitlement of all other countries.

(K). Per capita Net Carbon Debt = per capita Carbon Debt (I) minus per capita Carbon Credit ((J): $10,058 (the World), $53,813 (EU), $114,842 (US), $4,706 (China), $39,723 (Japan), $107,849 (Germany), $50,161 (France), $123,856 (UK), $4,631 (Brazil), $67,724 (Russia), $55,522 (Italy), minus $5,144 (India), $58,295 (Canada), $88,575 (Australia), $4,843 (Indonesia), $4,289 (South Africa), $1,192 (Nigeria), minus $851 (Pakistan), and minus $10,926 (Bangladesh). Note that India , Pakistan and Bangladesh have negative Carbon Debt i.e. they have positive Carbon Credits.

(L). Total Carbon Debt in trillions of dollars can be calculated from the data in (K) by simply multiplying by the country or region population i.e. multiplying (B) by (K): $71.550 trillion (the World), $39.768 trillion (EU), $36.370 trillion (US), $6.401 trillion (China), $5.057 trillion (Japan), $9.167 trillion (Germany), $3.296 trillion (France), $7.890 trillion (UK), $0.973 trillion (Brazil), $9.718 trillion (Russia), $3.315 trillion (Italy), minus $6.350 trillion (India), $2,052 trillion (Canada), $2.055 trillion (Australia), $1,151 trillion (Indonesia), $0.227 trillion (South Africa), $0.207 trillion (Nigeria), minus $0.157 trillion (Pakistan), and minus $1.666 trillion (Bangladesh). Note that India , Pakistan and Bangladesh have negative Carbon Debts i.e. they have positive Carbon Credits.

If this analysis has not been presented above for your country, you can readily do it using the steps outlined above. Is your country a Carbon Debtor (like the US, Canada and Australia) or a Carbon Creditor (like India, Pakistan and Bangladesh)?

Conclusions.

Assessment of the biochar-based cost of returning the atmospheric CO2 concentration from the current dangerous 400 ppm CO2 to a safe and sustainable 300 ppm CO2 reveals a staggering world Historical Carbon debt of $127 trillion, about twice the annual GDP of the whole World, with the major contributors being the EU (31.9%), the US (28.6%), China (8.5%) and Russia (7.7%).

In terms of biochar-based per capita Historical Carbon Debt, the worst polluters have been the US, the EU countries, Russia, Japan, Canada and Australia. Yet these are also the worst countries in terms of current annual per capita greenhouse gas pollution – thus the world average is 5.9 tonnes CO2-e per person per year but the US, the EU countries, Russia, Japan, Canada, Australia, Indonesia, and South Africa are well above this, China is slightly below the average, and India, Nigeria, Pakistan and Bangladesh fall well below the average.

The countries of the world fall into 2 categories – the Carbon Debtors (notably the US, Canada and Australia) and the Carbon Creditors (notably India, Pakistan and Bangladesh). The European countries in general and Japan have left an appalling Carbon Debt for future generations in their own countries and around the world. This represents an appalling example of intergenerational inequity and intergenerational injustice.

Since we have a global capitalist economy based on the bottom line that debts must be repaid, people in the Developing World and China should insist that the Carbon Debt is paid in full by those responsible for it.

Those climate criminal leaders and countries unwilling (a) to end their disproportionately high greenhouse gas pollution or (b) to pay their huge Carbon Debt should face exposure, Boycotts, Divestment and Sanctions (BDS), Green Tariffs, sporting bans, litigation before the International Court of Justice and arraignment before the International Criminal Court.

The climate criminals must be held accountable by young people in particular and by future generations. The world economy can no more be based on theft and mendacity.

References.

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[2]. “300.org – return atmosphere CO2 to 300 ppm”, 300.org: http://sites.google.com/site/300orgsite/300-org---return-atmosphere-co2-to-300-ppm .

[3]. Long Cao and Ken Caldeira, “Atmospheric carbon dioxide removal: long-term consequences and commitment”, Environmental Research Letters, 5(2) (2010): http://iopscience.iop.org/1748-9326/5/2/024011 .

[4]. “Carbon capture and storage”, Wikipedia: http://en.wikipedia.org/wiki/Carbon_capture_and_storage .

[5]. Ken Caldeira and Greg H. Rau, “Accelerating carbonate dissolution to sequester carbon dioxide in the ocean: geochemical implications”, Geophysical Research Letters, 27 (2), 225-226 (2000): http://onlinelibrary.wiley.com/doi/10.1029/1999GL002364/abstract .

[6]. Greg H. Rau, Ken Caldeira, Kevin G. Knauss, Bill Downs and Hamid Sarv, “Enhanced carbonate dissolution as a means of capturing and sequestering carbon dioxide”, First National Conference on Carbon Sequestration, Washington DC, May 14-17, 2000: http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/p24.pdf .

[7]. G.H. Rau, “CO2 mitigation via capture and chemical conversion in seawater”, Environ Sci Technol 45:1088–1092, 2011: http://pubs.acs.org/doi/abs/10.1021/es102671x .

[8]. IPCC, “Summary for policymakers”, 2013: http://www.climatechange2013.org/images/uploads/WGIAR5-SPM_Approved27Sep2013.pdf .

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[11]. Kevin Bullis, “Capturing and storing carbon dioxide in one simple step”, MIT Technology Review, 20 September 2013: http://www.technologyreview.com/news/519406/capturing-and-storing-carbon-dioxide-in-one-simple-step/ .

[12]. James Hansen et al, (2007), “Target atmospheric CO2: where should humanity aim?”, Open Atmos. Sci. J. (2008), vol. 2, pp. 217-231 : http://arxiv.org/abs/0804.1126 and http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf .

[13]. Progress in Thermochemical Biomass Conversion, volume 1, IAE Bioenergy, ed. A. V. Bridgewater (Blackwell Science): http://books.google.com.au/books?id=rdqGX0LEg7sC&pg=PA224&lpg=PA224&dq=Gt++biomass+%22arable+land%22&source=bl&ots=KfEmoUUg6T&sig=EuLvPTf4uJHK6Wq7jbpQ3WLHcnM&hl=en&ei=UdzISZXlDpmMsQPH3cyMAQ&sa=X&oi=book_result&resnum=1&ct=result#PPP1,M1 .

[14]. Gideon Polya, “Forest biomass-derived Biochar can profitably reduce global warming and bushfire risk”, Yarra Valley Climate Action Group: https://sites.google.com/site/yarravalleyclimateactiongroup/forest-biomass-derived-biochar-can-profitably-reduce-global-warming-and-bushfire-risk .

[15]. Alok Jha, “”Biochar’ goes industrial with giant microwaves to lock carbon in charcoal”, Guardian (13 March 2009): http://www.guardian.co.uk/environment/2009/mar/13/charcoal-carbon .

[16]. Johannes Lehmann, Biochar for mitigating climate change: carbon sequestration in the black”: http://www.geooekologie.de/download_forum/forum_2007_2_spfo072b.pdf .

[17]. "James Lovelock on Biochar: let the Earth remove CO2 for us", UK Guardian, 24 March 2009: http://www.guardian.co.uk/environment/2009/mar/24/biochar-earth-c02 .

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[19]. The present Carbon Cycle”, Green World Trust: http://www.greenworldtrust.org.uk/Science/Images/CO2/CO2cycle.jpg .

[20]. Simon Shackley, Jim Hammond, John Gaunt and Rodrigo Ibarrollo, “The feasibility and costs of biochar deployment in the UK ”, Carbon Management, 2(3), 335-356 (2011): http://www.geos.ed.ac.uk/homes/sshackle/CostsBiochar.pdf .

[21]. “List of countries by GDP (nominal)”, Wikipedia: http://en.wikipedia.org/wiki/List_of_countries_by_GDP_%28nominal%29 .

[22]. “List of countries by population”, Wikipedia: http://en.wikipedia.org/wiki/List_of_countries_by_population .

[23]. Robert Goodland and Jeff Anfang. “Livestock and climate change. What if the key actors in climate change are … cows, pigs and chickens?”, World Watch, November/December 2009: http://www.worldwatch.org/files/pdf/Livestock%20and%20Climate%20Change.pdf .

[24] “List of countries by greenhouse gas emissions”, Wikipedia: http://en.wikipedia.org/wiki/List_of_countries_by_greenhouse_gas_emissions .

[25] “Letter to PM Kevin Rudd by Dr James Hansen”, 2008: http://www.aussmc.org.au/documents/Hansen2008LetterToKevinRudd_000.pdf ).
[26]. “Carbon Debt, Carbon Credit”: https://sites.google.com/site/carbondebtcarboncredit/home .

[27]. Gideon Polya, “Shocking analysis by country of years left to zero emissions”, Greenblog, 1 August 2011: http://www.green-blog.org/2011/08/01/shocking-analysis-by-country-of-years-left-to-zero-emissions/ .