Many have heard that science shows that in order to avert the worst of climate catastrophe, we not only must reduce our emissions dramatically, but also ensure that the total accumulated greenhouse gases (GHGs) in the atmosphere is reduced swiftly from the present 387 parts-per-million (ppm), to below 350 ppm (pre-industrial level was around 275 ppm).

But how does that translate into emission reduction targets and a time line?

Numbers are flying around everywhere – all claiming to be what best science determines to be necessary.  Many governments claim their targets that aims for 20% reduction below 1990 levels by 2020, and 80% below 1990 levels by 2050, is heeding IPCC advice (the US climate legislation, Waxman-Markey and its Senate counterpart, Boxer-Kerry, are far less ambitious).  Not true!  Some who bothered to read into the IPCC report said developed countries need to cut 25-40% below 1990 levels by 2020, and 80-95% by 2050.  Unfortunately that’s only aiming for stabilizing at 450 ppm (after a projected overshoot of 50 ppm that is hoped to be temporary), which produces about a 50% chance of overshooting 2 degree Celsius rise above pre-industrial temperature.  Even the group of island nations that demanded the strongest targets yet from industrialized world was asking for only “at least 40%” reduction from 1990 leveks by 2020.  As I discussed in a previous blog, the IPCC worst case scenario trajectories or worse has been realized, according to the 2,000 scientists at the Copenhagen Climate Science Congress earlier this year.  This means that even aiming for the 450 ppm stabilization level requires at least the stronger end of IPCC’s benchmark reduction targets – i.e., at least 40% below 1990 by 2020, and at least 95% below 1990 by 2050 in developed countries.

So how DO we return below 350 ppm?  The short answer is, no one has carefully defined a clear path yet, as far as I know (and if you’ve seen a good study, please email me).

It is critically important that a clear, viable and safe pathway leading to below 350 ppm in the very near term, be identified and articulated, and all methods/tools utilized on that pathway be carefully evaluated by interdisciplinary panels of climate, ecological, marine, soil, forestry, agricultural, geological and other scientists, as well as energy and technology experts, to ensure that these are effective real solutions, not false solutions that are just tools for some industries or other to profit off of climate legislation.

Before I offer our ideas on such a path, here is my critique on the path sketched out by the scientists who first identified this target concentration itself.

Hansen et al's 2008 paper on target CO2[1], which identified 300-350ppm as the upper limit for a safe climate, also outlined in general terms how we might achieve that, including the linear phase-out by 2030 of all coal fired power plants that don’t capture 100% CO2..  But their path seems overly optimistic in terms of believing in our ability to return below 350 ppm even with a relatively leisurely speed of phasing out fossil fuels, for the following reasons:

·         Their projection that if coal is phased out by 2030, we could use up all ready-to-extract oil and gas that's already in the IPCC version of the world reserve estimate, and still return below 350 ppm if other measures are taken (see below), is at odds with a recent Nature paper[2] (the trillion ton paper by Meinshausen et al).  Fig 3 of that paper shows that burning all the economically recoverable oil and gas reserve alone will exceed the 1 trillion ton CO2 budget for 2000-2049, a budget that carries a 25% probability of exceeding 2 degrees Celsius warming above pre-industrial temperature.  Stabilizing at 350 ppm is supposed to produce about a 7% probability of exceeding 2 degrees C[3], therefore it should have been more stringent than the 1 trillion ton carbon budget – meaning that we will not be able to use up all ready-to-extract oil and gas, if we are to aim for 350 ppm.

·         They assume that nuclear power can continue to be relied upon as a “renewable energy” in place of fossil fuel and presumed to be carbon free.  Not only is nuclear fuel mining and processing destructive to the environment and health, nuclear waste disposal will continue to be an unsolved problem for the foreseeable future.  More over, as higher grades and more readily mined nuclear fuel is already being depleted, the lower grades are much more energy-intensive to extract - same problem as oil shale and tar sand.  The lifecycle emission from power plant construction, mining, milling, processing, and transporting raw material and waste for a nuclear power plant, can be comparable to a gas-fired power station per unit energy output, and in the case of very low grade ores, exceed the latter for the entire life time of a nuclear reactor[16].  Even with the highest grade ores, due to the front loading of heavy emissions from nuclear power plant construction, it takes at least 7 years for a nuclear plant to “overtake” a gas power plant in terms of lower CO2 emissions.  Considering our time line of less than 10 years to avert crossing the point of no return in the climate system, clearly nuclear power is not our answer.  They are by no means carbon free as the nuclear industry falsely claims.

·         They assume that global deforestation drops quickly to zero between 2010 and 2015 (currently deforestation accounts for 12-25% of annual global anthropogenic emissions[4-7]).  While this is almost certainly necessary for any scheme to successfully return GHGs to below 350 ppm, currently it does not look optimistic.  With the UN process as well as the US climate legislation increasingly relying on massive amounts of forest/agricultural “offsets” or carbon credits (called REDD in the UN programs) to mock up the non-existent smokestack emission reduction, which also perversely encourages conversion of natural forests to monoculture plantations (e.g., palm) capable of sequestering only up to 1/5 of the carbon as intact forests[8], this rapid deforestation-ending schedule Hansen et al assumes is certainly not on track to be met – if one is not to double/triple count any real reductions in deforestation for the purpose of emission reductions accounting.

·         Their scenario assumed that biochar produced on biomass grown on “degraded/marginal lands” and buried into the soil can be widely deployed as a carbon drawdown method and have positive effects on soil health everywhere.  This has a number of problems, including but not limited to:

1. The effect of biochar on soil health is not always positive.
2. Large scale deployment that would make a substantial difference in terms of carbon drawdown with this method, would likely lead to decimation of forests and other natural environments, as the classification of “degraded land” is so creatively applied in response to regulatory requirements.

·         They also didn't carefully consider non-CO2 GHGs, which may in part account for the vastly different outlook of their paper from a 2008 paper from the Tyndall Center[9].  In that study, Anderson and Bows assumed deforestation and non-CO2 GHG emissions will both peak in 2015 before dropping precipitously, with deforestation dropping eventually to zero, and non-CO2 GHG emissions - which the authors attributed mostly to food production - dropping to half the current intensity per world capita assuming genuine global actions, stabilizing at 7.5 GtCO2e/year.  With these assumptions, the authors reached the conclusion that, our chances of even stabilizing at 450 ppm can be pretty much ruled out except under the most optimistic of the range of IPCC climate sensitivity estimates (more recent studies indicated the optimistic climate sensitivity estimates not to be true), even if emissions from energy production and industrial processes became instantly zero after peaking in 2015!

·         Neither Hansen et al nor the Tyndall paper (or the IPCC 2007 report) built into their models any consideration of the amplifying effect of large quantities of methane found to be releasing from under the sea bed and from permafrost, the dynamic processes of melting ice that is very different from, and much faster than linear surface melting, the impending loss of Arctic sea ice with the consequent large loss of ice reflectivity in summer, or the recent evidence of the decline in the efficiency of carbon sinks[10,11,17], both in ocean[12,13] and on land[14,15].  Increased emissions from much more frequent and intense forest fires in multiple continents, from the die-off carbon emissions due to severe droughts, flooding and other ecosystem traumas, are generally not taken into account.

Now, here is what I think needs to be done to return below 350 ppm:

Given that there are many indications of accelerating warming, and given that rapid acceleration is associated with crossing tipping points, staying above 350 ppm for even a few more decades seems too risky.  We also can not continue to rely on ocean uptake of excess CO2, due to the serious problem of ocean acidification.  In fact we must rapidly sequester CO2 from the atmosphere to halt the acidification process.  Therefore, I propose that every effort should be made to return to below 350 ppm no later than 2030.  Incidentally, that will mean an average reduction of about 2 ppm/year, on the same scale as the current rate of increase.

First of all, emissions from all sources must be reduced as close to zero as possible, by 2020.  Meanwhile, there are very promising natural carbon sequestration methods that we can implement IMMEDIATELY to store huge quantities of carbon VIA LIVING PROCESSES into the soil and terrestrial biosphere.  These methods will also restore soil health, repair damaged ecosystems, and provide food and sustenance for billions of people.  Virtually all known geo-engineering ideas, on the other hand, have serious and mostly unpredictable consequences, and if we do the above two things right away, we probably never have to even contemplate on any of them.

Note that this discussion only deals with what is needed to be achieved, not which policies are needed to achieve these goals.  That is the subject of a separate discussion posted soon here.

·        Eliminate the vast majority of emissions from fossil fuels by 2020 – that means, leaving fossil fuels in the ground!  We can not rely on Carbon Capture & Sequestration (CCS), even if it becomes available some day, because it will threaten future generations with massive underground CO2 time bomb through inevitable leakage from fault lines, etc., which will undo the capturing in the first place, while wasting the energy that went into the capturing and storage itself (the capturing step costs at least a fifth of energy from coal), and threatening the health of surface soil, aquatic life, and human safety (Greenpeace).  The State of the World Forum, co-founded by Nobel Peace laureate Mikhail Gorbachev, aspired at its recent 13th annual conference to originate a global 2020 Climate Leadership Campaign to cut carbon emissions 80 percent by 2020 and "call on world leaders and concerned citizens everywhere" to join it.  And, a blueprint for cutting global emissions by 80% below 2006 levels by 2020 was already laid out by Lester Brown of the Earth Policy Institute in his book “Plan B 4.0: Mobilizing to Save Civilization”.  Only with a war-time global mobilization to drastically and purposefully contract and conserve, and to redirect economic activities into energy efficiency improvements, renewable energy, public transportation, re-localized agriculture that minimizes transportation needs, etc., will such drastic reduction be possible.  For many big economies of the world, especially the US, re-directing military spending for this effort is the lowest hanging fruit and most consistent with a global cooperative spirit (US military spending amounts to at least half of its income tax revenues each year).  One particularly expedient way to reduce the global warming impact quickly, is to dramatically cut down on black soot emission, which results from incomplete combustion of fossil fuels, bio-fuel (e.g., wood for stoves and heating), and open biomass burning (e.g., forest fires, agriculture and land-clearing fires).  Black carbon is relatively short-lived (days to weeks) in the atmosphere, yet has a very large warming impact both through haze formation and through ice albedo changes, so reducing black carbon can have a large immediate effect.

·        At the same time, completely abolish all unsustainable agricultural practices as quickly as possible, and switch to sustainable, holistic soil management practices that respect and work with the harmonious relationship among all species in any given ecosystem that co-evolved over millennia.  This includes Allan Savory’s pioneering approaches on restoring the world’s mostly degraded rangelands with pulsed grazing, that increase soil organic matter and hence sequester large amounts of carbon while restoring rangeland health and water storage capacity, reversing desertification, and providing meat at the same time.  This also includes breaking away from the “conventional” crop production methods that are expensive (both in dollars and in cost to human and environmental health), that rely on fossil fuel based fertilizers, long distance transportation, genetically modified crops, pesticides and herbicides, and instead implement a worldwide switch to organic, sustainable agriculture with a particular emphasis on keeping the soil covered, something nature always does.  With rapid global implementation, the holistic management system holds promise to reducing atmospheric CO2 concentration by tens of ppm in less than 15 years.  See here for our more detailed introduction about sustainable/holistic agriculture.

·        Ending global deforestation and ecosystem destruction is of utmost urgency.  No offsets should be allowed, and no monoculture plantation style reforestation or aforestation should be rewarded.  Restoring ecosystems including forests and peatlands should be the primary focus.  Once the native rainforests are clearcut or severely damaged, we lose along with them countless species that constitute the biodiverse web of life that provides not only ecosystem stability, but also climate stability.  Rainforests are a major climate regulator/stabilizer.  As with most complex systems in nature, ecosystem collapses and climate feedback systems are all non-linear, that can collapse/tip suddenly upon significant stress.  When a tree is felled in the rainforest, its carbon content that often took centuries to accumulate is released rapidly into the atmosphere, one way or another.  This in itself constitutes a huge flush of carbon emissions, and as mentioned above, comprise as much as 12-25% of annual global anthropogenic emissions.  Not only do we need to stop deforestation immediately (mostly in developing countries), we must ensure this is done IN ADDITION TO emission reductions from fossil fuels, and not IN PLACE OF, as is the case with REDD offset schemes, or the US House and Senate climate bills Waxman-Markey and Boxer-Kerry.  Please see here for further discussion of the crippling loopholes in REDD and US climate bills, and the policy  alternatives in these areas that should be used instead.

·        Population contraction is an obvious necessity if we are to claim ourselves a species of any intelligence.  It is indeed a human rights issue, in that the rights of the human race itself (and those of most of the species on this planet) will be most severely violated through uncontrolled human population growth that breaks the sustaining capacity of our planet, aiding all the other stresses we are imposing on it.  When done equitably on a global scale, and with proper education, there is no violation of human rights by planned contraction of population size, because we all share the same responsibility and the same interest in ensuring a fair chance for the survival of the human race.

·        All of these require an awakening of humanity’s consciousness of where our place is in nature, in order to properly move ourselves into that place, to live in harmony with our ecological environment instead of destroying it.  In much of the world where corporate greed dominates political, economic, cultural and military affairs and dictates all policies including climate and environmental policies, this requires radical changes to the laws and structures of how societies are run, that need to result in ending corporate rule and restoring/installing democracy in its rightful place, so as to allow truthful information to reach billions of people whose decisions and actions will together determine our future.

In short, to return below 350 ppm is not just a technical or policy problem.  It is a political, social, ideological problem as it is every bit a survival problem.  Our odds are slim, for all the changes that are required to get from here to there.  But, what other options do we have?

References:

[1] Hansen, J., Mki. Sato, P. Kharecha, D. Beerling, R. Berner, V. Masson-Delmotte, M. Pagani, M. Raymo, D.L. Royer, and J.C. Zachos, 2008: Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J., 2, 217-231.

[2] Meinshausen, M., N. Meinshausen, W. Hare, S. C. B. Raper, K. Frieler, R. Knutti, D. J. Frame and M. R. Allen (2009). "Greenhouse-gas emission targets for limiting global warming to 2°C." Nature 458(7242): 1158.

[3] Meinshausen, M. (2006): 'What does a 2°C target mean for greenhouse gas concentrations? A brief analysis based on multi-gas emission pathways and several climate sensitivity uncertainty estimates', pp.253 – 280 in Avoiding dangerous climate change, H.J. Schellnhuber et al. (eds.), Cambridge: Cambridge University Press.

[4] Anderson K, Bows A. Reframing the climate change challenge in light of post-2000 emission trends. Philos Transact R. Soc. A Math Phys Eng Sci. 2008 Nov 13;366(1882):3863-82.

[5] IPCC AR4 WGI (2007): Solomon SD, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, and Miller HL (eds), Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the IPCC (Cambridge University Press, Cambridge, 2007), Chapter 7.3

[6] Houghton, R.A., 2003a: Revised estimates of the annual net fl ux of carbon to the atmosphere from changes in land use and land management 1850-2000. Tellus, 55B(2), 378–390.

[7] Houghton, R.A., 2003b: Why are estimates of the terrestrial carbon balance so different? Global Change Biol., 9, 500–509.

[8] Friends of the Earth report, Dec 2008: REDD myths - a critical review of proposed mechanisms to reduce emissions from deforestation and degradation in developing countries http://action.foe.org/pressRelease.jsp?press_release_KEY=445

[9] Anderson & Bows, 2008

[10] Carbon Budget 2007 report: “The efficiency of natural sinks has decreased by 5% over the last 50 years (and will continue to do so in the future)” http://www.globalcarbonproject.org/carbonbudget/07/index.htm

[11] Canadell, J. G. et al. Contributions to accelerating atmospheric CO₂ growth from economic activity, carbon intensity, and efficiency of natural sinks. Proc. Natl Acad. Sci. USA 104, 18866–18870 (2007)

[12] Corinne Le Quéré, Christian Rödenbeck, Erik T. Buitenhuis, Thomas J. Conway, Ray Langenfelds, Antony Gomez, Casper Labuschagne, Michel Ramonet, Takakiyo Nakazawa, Nicolas Metzl, Nathan Gillett, Martin Heimann(2007) Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change  Science 22 June 2007: Vol. 316. no. 5832, pp. 1735 – 1738 DOI: 10.1126/science.1136188

[13] Schuster, U., and A. J. Watson (2007), A variable and decreasing sink for atmospheric CO₂ in the North Atlantic, J. Geophys. Res., 112, C11006, doi:10.1029/2006JC003941. Full article avail. Here.

[14] Steven W. Running "Ecosystem Disturbance, Carbon, and Climate" Science 1 AUGUST 2008 VOL 321 pp. 652-653

[15] Cranmer, W. et al 2001 Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models. Glob. Change Biol. 7, 357-373. (doi:10.1046/j.1365-2486.2001.00383.x)

[16] Storm van Leeuwen, J.W and Philip Smith. “Nuclear Power: the Energy Balance.” Chapter 1: The CO2-Emission of the Nuclear Lyfe-Cycle. 2005.

[17] Thornton, P. E., Doney, S. C., Lindsay, K., Moore, J. K., Mahowald, N., Randerson, J. T., Fung, I., Lamarque, J.-F., Feddema, J. J., and Lee, Y.-H.: Carbon-nitrogen interactions regulate climate-carbon cycle feedbacks: results from an atmosphere-ocean general circulation model, Biogeosciences, 6, 2099-2120, 2009.