Sustainable Land Management for Mitigating Climate Change

II. Rationale and Context

7. While 75% of the global poor are rural and mainly agrarian, it is also clear that agriculture is and will remain the driver of economic growth in many developing countries, where it often represents at least 25% of GDP. But the quality and productivity of the land depends on the way agriculture is practiced. Better agricultural techniques will necessarily include SLM. And appropriate SLM practices can contribute to agriculture productivity improvements. Combating LD via SLM can lead to increase in land productivity while also improving the environment and mitigating CC. These improvements and ancillary benefits are a direct consequence of increase in quantity and quality of Soil Organic Matter (SOM), as a result of: a) increase in accumulation of organic residues above and below (roots) the soil surface, and b) decrease in oxidation/decomposition rate of organic residues and of inherent SOM content (due to lower surface temperature, more CO₂ and less O₂ in the soil pores, no incorporation of residues), and decline in losses of SOM because of decline in risks of soil erosion by water and wind.

8. The value of SLM can be enhanced to accentuate both local and global benefits by harnessing its potential to sequester carbon (C) in the terrestrial ecosystems including soil and above ground biomass, and hence directly contributing to CC mitigation (Lal 2006). Other SLM practices such as perennial cover-cropping (e.g., with drought tolerant shrubs and trees) can enhance the ability of areas to be more resilient to extreme climate variability and change (e.g., droughts) while also sequestering C. Hence, investments in SLM can yield livelihood, development, environmental and climate benefits. Therefore, SLM and agricultural growth are not and should not be just about farming and food commodities. Producers will only practice SLM if it pays to do so; hence land degradation mitigation strategies must be designed and implemented as part of the broad and specific development agenda, with the needs of the local communities as their primary focus. Producers (especially poor farmers) would increasingly need to be facilitated into non-traditional and often value-added opportunities such as payments for ecosystem services (PES) and C markets.

9. The objectives of SLM are consistent with many core World Bank policies and strategies that address poverty reduction, rural development and environmental management. The World Bank is already one of the leading financiers of SLM globally. The 2008 WDR advocates improved livelihoods in sustainable agriculture as one of the pathways out of poverty. Improving the livelihoods of subsistence farmers includes improving land productivity and increasing the resilience of farming systems to reduce risk and food insecurity through better natural resource management (NRM). Given its commitment to addressing CC in its operations, the World Bank Group has recently developed the Strategic Framework on Development and Climate and Change (SFDCC) which puts priority on strengthening the resilience of communities and economies to climate risks. This, together with other strategies (e.g., Environment Strategy, Reaching the Rural Poor: a Renewed Strategy for Rural Development, etc) set the framework for investments in SLM (World Bank, 2001, 2003, 2008). In order to achieve the objectives set out in the strategies, it is important for the World Bank to ensure that its SLM investments capture the synergies and trade-offs between poverty alleviation and climate change action in a targeted and sustainable manner.

SLM-based Carbon Sequestration contributes to Mitigating Climate Change and Greenhouse Gases

10. The two principal sources of the increase in atmospheric carbon (C) pool are fossil fuel combustion and deforestation/land use change (Broecker 2007; IPCC 2007). In the tropics and sub-tropics, deforestation and land use change constitute the principal sources. Whereas nutrients (e.g., N, P, K, S) released by decomposition and burning of biomass are absorbed by crops, C is released into the atmosphere as CO₂ and CH₄ along with nitrogen as N₂O and NO_x. Hence, agricultural practices can render a soil either a sink or a source of greenhouse gases (GHGs, particularly CO₂), with direct influence on the greenhouse effect and the attendant CC (Lal 2004; Lal 2005). Agricultural practices that lead to emissions of GHGs from the soil to the atmosphere include: deforestation (CO₂, CH₄, N₂O), biomass burning (CO₂, CH₄, N₂O), plowing and soil disturbance (CO2), draining of wetlands (CO₂, N₂O), and uncontrolled grazing (CO₂, N₂O). Emission of these gases from agricultural ecosystems is enhanced by subsistence agricultural practices which do not invest in soil quality improvement practices such as erosion control, water management, and application of fertilizers and other amendments.

11. Sequestration of C in terrestrial ecosystems (soils and trees) is widely recognized as a viable strategy to mitigate CC while providing numerous ancillary benefits by also enhancing ecosystem services (such as increased soil productivity, enhanced rainfall infiltration, aquifer recharge, etc). The available data on C sequestration from diverse soils and ecoregions show the significant contribution that improved soil management can play in C sequestration and mitigation of the greenhouse effect (Lal 2006). Technological options for C sequestration in soil include conservation tillage, mulch farming, integrated nutrient management (INM) including use of manure and biochar, restoration of degraded soils, composting, integrated pest management (IPM), landscape reclamation through afforestation, elimination of bare fallow, and improved pasture management (Lal 2004). Conservation tillage offers the best option for C sequestration in: (a) temperate humid and semi-arid areas, and (b) tropical and sub-tropical humid areas.