Big Facts on Climate Change, Agriculture and Food Security

Forestry and Land Use

Facts
  • There are four major strategies for mitigating carbon emissions through forestry activities:
    • increasing forested land area through reforestation;
    • increasing carbon density of existing forests at stand and landscape scales by, for example, employing longer harvesting cycles or reducing disturbance (Candell and Raupach 2008);
    • reducing emissions from deforestation and degradation; and
    • expanding the use of forest and agroforestry products that sustainably substitute fossil fuel carbon emissions (Nabuurs et al. 2007).
  • Globally, forestry mitigation options could sequester 1,270–4,230 million tonnes of carbon dioxide equivalent per year in 2030 at carbon prices up to USD 100 per tonne of carbon dioxide (CO2) equivalent. Achieving about half of this mid-range estimate would cost less than USD 20 per tonne of CO2e (Nabuurs et al. 2007; Candell and Raupach 2008).
  • A 10% reduction in deforestation would cost USD 0.4–1.7 billion per year and would reduce emissions by 300–600 million tonnes of CO2 equivalent from 2005 to 2030 (Kindermann et al. 2008).
  • Policy incentives are key to increasing forest carbon sinks and to ensuring that conserving forests is more beneficial than clearing them (Grieg-Gran 2010). Economic incentives will enable the forestry sector to compete with other land uses (agriculture, urban development, recreation) that limit forest mitigation opportunities (Jackson and Baker 2010).
  • Moist tropics have the most forestry mitigation potential (Nabuurs et al. 2007).
  • Converting arable land to woodland increases soil organic carbon by 44–64 tonnes of carbon per hectare (161–234 tonnes of CO2 equivalent per hectare) over a 120-year period. (Powlson et al. 2011).
  • Forestry mitigation potential differs significantly across countries and over time. The factors influencing this potential are the amount of land available and suitable for forestation, present and future land-use activities, carbon sequestration potential and changes in the efficiency of forest products (Sathaye et al. 2007).
  • Limits to mitigation through forestry and land use include:
    • obstacles to measuring carbon stock changes;
    • concerns regarding their potential reversibility or the non-permanency of forest carbon stocks (e.g. removal by illegal harvest or wildfires);
    • the threat of unintended environmental and socioeconomic impacts of reforestation programmes (Candell and Raupach 2008);
    • uncertainty around Kyoto accounting rules;
    • leakage or displacement of emissions; and
    • financial constraints due to high transaction costs (Murphy et al. 2009).
  • A landscape approach—not forestry alone—is needed to abate emissions from change in land use. Even if deforestation were halted entirely, as much as 50% of potential reductions in emissions would be diverted to other landscapes if agriculture continued to expand at historical rates (Creed et al. 2010).
  • Agriculture is the main driver for an estimated 80% of deforestation across the globe (Kissinger et al. 2012). However, the mitigation potential of forestry associated with agriculture is difficult to estimate.
  • Competition for land is expected to intensify as a result of economic and population growth, increased demand for food and bioenergy as well as demands for land conservation and urbanization (Smith et al. 2010). Mitigation in the AFOLU sector may affect this competition. Demand side mitigation generally lowers input and land requirements, lessening competition (Smith et al. 2013). Supply side options for mitigation are more complex in their impacts on land use competition. Resource efficiency measures and intensification of production can reduce competition for land. But where such measures are implemented unsustainably, additional tradeoffs with other ecological, social, and economic costs may arise (IAASTD, 2009).
  • Mitigation in the AFOLU sector needs to integrate energy, agriculture and land use management in order to find synergies and minimize tradeoffs. For example, opportunities to harvest bioenergy can provide the incentive to restore or stabilize degraded land, resulting in synergistic benefits for energy production, mitigation and land use (Wicke et al., 2011; Sochacki et al., 2012; Harper et al., 2007). However, bioenergy production may also be a point of tension in some regions, as it can leave less land available for growing food and may reduce yields due to competition for inputs. In the case of ethanol produced from maize, energy markets absorb an agricultural product that would otherwise be used for food (Smith et al. 2013).
  • Heating biomass in the absence of oxygen generates carbon rich char. By adding char to soil as 'biochar', the rate at which photosynthetically fixed carbon is returned to the atmosphere is inhibited. Estimates of the mitigation potential of biochar at the global scale range from 3.7-6.6 GtCO2eq/yr, accruing 240-480 GtCO2eq abatement within 100 years (Woolf et al., 2010).
  • Application of biochar can also yield several potential co-benefits. It can be burned as a source of renewable bioenergy; it can improve agricultural productivity, particularly in low-fertility and degraded soils where it can be especially useful to the world's poorest farmers; it helps fix nutrients and reduces the losses in run-off; it can increase the water-holding capacity of soils; and provides a way of making productive use of biomass waste (Woolf et al., 2010).
  • Governance and monitoring systems established for the Reducing Emissions from Deforestation and Forest Degradation (REDD) scheme could provide useful experience as policy makers look toward setting up a comparable global mitigation scheme for agriculture and land use. For example, REDD uses standards and safeguards to ensure that projects have positive environmental and social impacts beyond pure mitigation objectives. In the context of agriculture, the key outcomes to be secured include food security, livelihoods and economic development (Negra and Wollenberg, 2011).
  • Agroforestry systems offer a potential for soil and biomass carbon sequestration of up to 0.6 Gt C per year by 2040 (Verchot et al. 2007).
  • In general, agroforestry systems provide higher soil carbon stocks compared to landscapes without agroforestry (Kumar and Nair 2011).
  • African agroforestry systems with scattered trees, such as savanna grazing lands, may offer little carbon sequestration potential (0.2-0.8 t/ha/yr) (Tschakert et al. 2004; Glenday 2008; Takimoto et al. 2008; Luedeling et al. 2011), whereas rotational woodlots and long-term fallows might offer up to as much as 5.8t/ha/yr (Nyadzi et al. 2003; Mbow et al. 2014). However, comparisons among different studies are difficult due to lack of standard protocols (Luedeling et al. 2011).
Sources and further reading
  • Candell JG, Raupach MR. 2008. Managing forests for climate change mitigation. Science 320(5882):1456–1457. (Available from http://dx.doi.org/10.1126/science.1155458)
  • Creed A, Strassburg B, Latawiec A. 2010. Agricultural expansion and REDD+: an assessment of risks and considerations to inform REDD+ and land use policy design. Policy Brief 9. Washington, DC: Terrestrial Carbon Group. (Available from http://www.terrestrialcarbon.org/Terrestrial_Carbon_Group__soil_ %26_vegetation_in_climate_solution/Policy_Briefs_files/TCG %20Policy%20Brief%209%20Agricultural%20Expansion%20 and%20REDD.pdf) (Accessed on 5 November 2013)
  • Glenday J. 2004. A Preliminary Assessment of Carbon Storage and the Potential for Forestry Based Carbon Offset Projects in the Kakamega National Forest, Kenya. Unpublished BSc. Paper.
  • Grieg-Gran M. 2010. Beyond forestry: why agriculture is key to the success of REDD+. IIED Briefing. London: International Institute for Environment and Development (Available from http://pubs.iied.org/pdfs/17086IIED.pdf) (Accessed on 5 November 2013)
  • Harper RJ, Beck AC, Ritson P, Hill MJ, Mitchell CD, Barrett DJ, Smettem KRJ, Mann SS. 2007. The potential of greenhouse sinks to underwrite improved land management. Ecological Engineering 29: 329–341
  • IAASTD. 2009. Agriculture at a Crossroads: Global Report. International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD).
  • Jackson RB, Baker JS. 2010. Opportunities and constraints for forest climate mitigation. BioScience 60:698–707. (Available from http://dx.doi.org/10.1525/bio.2010.60.9.7)
  • Kindermann G, Obersteiner M, Sohngen B, Sathaye J, Andrasko K, Ramesteiner E, Schlamadinger B, Wunder S, Beach R. 2008. Global cost estimates of reducing carbon emissions through avoided deforestation. PNAS 105(30):10302–10307. (Available from http://www.pnas.org/content/105/30/10302.full) (Accessed on 5 November 2013)
  • Kissinger G, Herold M, De Sy V. 2012. Drivers of deforestation and forest degradation: A synthesis report for REDD+ policymakers. Vancouver, Canada: Lexeme Consulting. (Available from http://www.decc.gov.uk/assets/decc/11/tackling-climate-change/international-climate-change/6316-drivers-deforestation-report.pdf) (Accessed on 5 November 2013)
  • Kumar M, Nair R, eds. 2011. Carbon Sequestration Potential of Agroforestry Systems. 1st ed. Dordrecht: Springer.
  • Luedeling E, Sileshi G, Beedy T, Dietz J. Carbon Sequestration Potential of Agroforestry Systems in Africa. In: Kumar M, Nair R, eds. Carbon Sequestration Potential of Agroforestry Systems. Dordrecht: Springer. p 61-83.
  • Mbow C, Smith P, Skole D, Duguma L, Bustamante M. 2014. Achieving mitigation and adaptation to climate change through sustainable agroforestry practices in Africa. Current Opinion in Environmental Sustainability 6:8-14. http://dx.doi.org/10.1016/j.cosust.2013.09.002
  • Murphy D, De Vit C, Nolet J. 2009. Climate change mitigation through land use measures in the agriculture and forestry sectors. Winnipeg, Canada: International Institute for Sustainable Development. (Available from http://www.iisd.org/pdf/2009/climate_change_mitigation_land_use.pdf) (Accessed on 5 November 2013)
  • Nabuurs GJ, Masera O, Andrasko K, Benitez-Ponce P, Boer R, Dutschke M, Elsiddig E, Ford-Robertson RJ, Frumhoff P, Karjalainen T, Krankina O, Kurz WA, Matsumoto M, Oyhantcabal W, Ravindranath NH, Sanz Sanchez MJ, Zhang X. 2007. Forestry. In: B Metz, OR Davidson, PR Bosch, R Dave, LA Meyer, eds. Climate change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. (Available from http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-chapter9.pdf) (Accessed on 5 November 2013)
  • Negra C, Wollenberg E. 2011. Lessons from REDD+ for agriculture. CCAFS Report No. 4. Copenhagen, Denmark: CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS).
  • Nyadzi GI, Otsyina RM, Banzi FM, Bakengesa SS, Gama BM, Mbwambo L, Asenga D. 2003. Rotational woodlot technology in northwestern Tanzania: Tree species and crop performance. Agroforestry Systems 59:253-263. http://dx.doi.org/10.1023/B:AGFO.0000005226.62766.05
  • Powlson DS, Whitmore AP, Goulding KWT. 2011. Soil carbon sequestration to mitigate climate change: a critical re-examination to identify the true and the false. European Journal of Soil Science 62:42–55. (Available from http://dx.doi.org/10.1111/j.1365-2389.2010.01342.x)
  • Sathaye JA, Makundi W, Dale L, Chan P, Andrasko K. 2006. GHG mitigation potential, costs and benefits in global forests: a dynamic partial equilibrium approach. Energy Journal 27(Special Issue 3):127–172. (Available from http://www.iaee.org/en/publications/ejissue.aspx?id=2183) (Accessed on 5 November 2013)
  • Smith P, Gregory PJ, van Vuuren DP, Obersteiner M, Havlík P, Rounsevell M, Woods K, Stehfest E, Bellarby J. 2010. Competition for land, Philosophical Transactions of the Royal Society B: Biological Sciences 365: 2941 –2957.
  • Smith P, Haberl H, Popp A, Erb K, Lauk C, Harper R, Tubiello FN, de Siqueira Pinto A, Jafari M, Sohi S, Masera O, Böttcher H, Berndes G, Bustamante M, Ahammad H, Clark H, Dong H, Elsiddig EA, Mbow C, Ravindranath NH, Rice CW, Robledo Abad C, Romanovskaya A, Sperling F, Herrero M, House JI, Rose S. 2013. How much land‐based greenhouse gas mitigation can be achieved without compromising food security and environmental goals? Global Change Biology 19: 2285–2302.
  • Sochacki SJ, Harper RJ, Smettem KRJ. 2012. Bio‐mitigation of carbon following afforestation of abandoned salinized farmland. GCB Bioenergy 4: 193–201.
  • Takimoto A, Nair R, Nair V. 2008. Carbon stock sequestration potential of traditional and improved agroforestry systems in the West African Sahel. Agriculture, Ecosystems & Environment 125:159-166. http://dx.doi.org/10.1016/j.agee.2007.12.010
  • Tschakert P, Khouma M, Sene M. 2004. Biophysical potential for soil carbon sequestration in agricultural systems of the Old Peanut Basin of Senegal. Journal of Arid Environments 59:511-533. http://dx.doi.org/10.1016/j.jaridenv.2004.03.026
  • Verchot LV, Van Noordwijk M, Kandji S, Tomich T, Ong C, Albrecht A, Mackensen J, Bantilan C, Anupama KV, Palm C. 2007. Climate change: linking adaptation and mitigation through agroforestry. Mitigation and adaptation strategies for global change 12:901-918. http://dx.doi.org/10.1007/s11027-007-9105-6
  • Wicke B, Sikkema R, Dornburg V, Faaij A. 2011. Exploring land use changes and the role of palm oil production in Indonesia and Malaysia. Land Use Policy 28: 193–206
  • Woolf D, Amonette JE, Street‐Perrott FA, Lehmann J, Joseph S. 2010. Sustainable biochar to mitigate global climate change. Nature Communications 1: 1–9.