Agriculture as a cause of Climate change
According to intergovernmental panel on climate change, Agriculture is one of the world’s largest industries; agricultural land alone covers 40-50% of the world’s land surface. The sector accounts for roughly 14% of global greenhouse gas per year that makes agriculture is a major contributor to climate change (IPCC 2007).
According to the Stern Review, in 2000, about 35% of greenhouse gas emissions came from non-energy emissions: 14% were nitrous oxide and methane from agriculture. Total global greenhouse gas contribution of agriculture from both direct and indirect sources reached up to 32%; the most prominent sources includes: land conversion to agriculture, nitrous oxide released from soils, methane from cattle and enteric fermentation (flatulence-produced methane emissions), biomass burning, rice production, manure, fertilizer production, irrigation, farm machinery and pesticide production. About 74% of total agricultural related greenhouse gas emissions originate in developing countries.
Livestock sector expansion also contributed to overgrazing, land degradation, and an important driver of deforestation in addition to its methane and nitrous oxide emissions from ruminant digestion and manure management, and is the largest global source of methane emissions. Greenhouse gas emissions footprint of livestock sector varies considerably among production systems, regions, and commodities, mainly due to variations in the quality of feed, the feed conversion efficiencies of different animal species and impacts on deforestation and land degradation. Besides the livestock production, the waterlogged and warm soils of rice paddies make rice production system a large emitter of methane from agriculture.
Effect of climate change in agriculture
The cumulative impact of climate will have economic consequences and potentially large implications for the wellbeing and sustainable development of rural populations. Fundamental to this are a wide range of cross-sectorial impacts affecting health, water and energy resources, ecosystems, and land use. The impacts of climate change to agriculture over the next 50 to 100 years may include:
- Changing spatial and inter-temporal variability in stream flows, onset of rain days, and dry spells (Strzepek and McCluskey, 2006 ),
- More frequent floods and droughts, with greater erosion rates from more intense rainfall events and flooding (Agoumi, 2003),
- Increased crop water requirements from higher temperatures, reduced precipitation and increased evaporation, with likely more negative impacts on dryland than irrigated agricultural systems (Dinar et al., 2009),
- Positive and negative production and net yield changes for key crops including maize, wheat, and rice, among others, over different time periods, resulting in changes in crop and management choices (e.g. irrigation, crop type) (Kurukulasuriya and Mendelsohn, 2006 ),
- Potentially lengthened growing seasons and production benefits to irrigated and dryland systems under mild climate scenarios (Thornton et al., 2006 ),
- Increased heat and water stress on livestock, with possible shifts from agriculture towards livestock management (i.e. stock increases) under increased temperatures with a different mix of more heat resistant species than today and possible benefits to small farms (Seo and Mendelsohn, 2006 ; Dinar et al., 2009).
- Higher temperatures in arid and semi-arid regions will likely depress crop yields and shorten the growing season due to longer periods of excessive heat.
Climate change will not equally affect all countries and regions, even if Africa represents only 3.6% of emissions, the (IPPC, 2007) report highlighted that Africa will be one of the continents that will be hard hit by the impact of climate change due to an increased temperature and water scarcity. The report pointed out that there is “very high confidence” that agricultural production and food security in many African countries will be severely affect by climate change and climate variability.
Climate change will likely have the biggest impact in equatorial regions such as sub-Saharan Africa. This means that countries already struggling with food security are likely to find they struggle still harder in the future. World Bank (2009) study that focuses on developing countries estimates that without offsetting innovations, climate change will ultimately cause a decrease in annual GDP of 4% in Africa. The Food and Agriculture Organization (FAO) warns that an increase in average global temperatures of just two to four degrees Celsius above pre-industrial levels could reduce crop yields by 15-35 percent in Africa and western Asia, and by 25-35 percent in the Middle East. While an increase of two degrees alone could potentially cause the extinction of millions of domestic and wild species that have a biodiversity and food security potentials.
Adaptation of Agriculture from climate change
The vulnerability of a system depends on its exposure and sensitivity to climate changes, and on its ability to manage these changes (IPCC, 2001). Three intuitive approaches appear to have informed the prioritization of adaptation programs of actions and strategies to climate change, namely: a) social vulnerability approach (addressing underlying social vulnerability); b) resilience approach (managing for enhanced ecosystem resilience); and c) targeted adaptation approach (targeting adaptation actions to specific climate change risks).
Climate change adaptation enhanced by altering exposure, reducing sensitivity of the system to climate change impacts and increasing the adaptive capacity of the system while simultaneously explicitly recognizing sector specific consequences. With this respect, adaptation in the agricultural sector seen in terms of both short-term and long-term actions. The provision of crop and livestock insurance, social safety nets, new irrigation schemes and local management strategies, as well as research and development of stress resistant crop varieties form the core of short-term responses. Long-term responses include re-designing irrigation systems, developing land management systems and raising finances to sustain adoption of those systems.
Safety nets are likely to become increasingly important in the context of climate change as increased incidence of widely covariate risks will require the coverage and financing that these sources may provide. Some of the options for adapting agriculture to climate change have related cost for Agricultural research, Irrigation efficiency, Irrigation expansion and development of Roads.
Improving the use of climate science data for agricultural planning can reduce the uncertainties generated by climate change, improve early warning systems for drought, flood, pest and disease incidence and thus increase the capacity of farmers and agricultural planners to allocate resources effectively and reduce risks. Better use of assessing risks and vulnerability and then developing the safety nets and insurance products as an effective response is already being piloted in some areas with fairly positive results (Barrett et al. 2007).
Mitigation of Agriculture for climate change
Climate change mitigation refers to an anthropogenic intervention to reduce the sources or enhance the sinks of greenhouse gases (FAO, 2011d). In other words, mitigation means taking action to reduce the causes of climate change by limiting the amount of heat trapping gases that emitted into the Earth’s atmosphere. Agriculture could increasing carbon sinks, as well as reducing emissions per unit of agricultural product. The agricultural sector: high mitigation potential with strong adaptation and sustainable development co-benefits.
Mitigation of greenhouse gas emissions in agriculture sector includes reduction of emissions, avoided the emissions and creating sinks that can remove emissions. Lower rates of agricultural expansion in natural habitats, agro-forestry, treating of degraded lands, reduction or using more efficient use of nitrogenous inputs, better management of manure, and use of feed that increases livestock digestive efficiency are some of the major mitigation options in agriculture.
soil carbon sequestration have nearly 90% of agriculture’s climate change mitigation potential could be realized, if carbon markets could introduce to “ provide strong incentives for public and private carbon funds in developed countries to buy agriculture-related emission reductions from developing countries. Soil carbon sequestration by improved land use and management can increase and maintain greater soil Carbon stocks (i.e., sequester C) include a variety of practices that either increase the amount of C added to soils (as plant residues and manure) and/or reduce the relative rate of CO2 released through soil respiration. Soil carbon sequestration practices include: 1) improved grazing land management, 2) improved crop rotations, 3) improved fallows, 4) residue management, 5) reduced tillage, 6) organic matter amendments, 7) restoration of degraded lands, 8) rewetting of cultivated organic soils and (9 Agroforestry. More over using improved nutrient management could increase the plant uptake efficiency of applied nitrogen, reduce N2O emissions, while contributing to soil C sequestration. Agroforestry systems tend to sequester much greater quantities of carbon than agricultural systems without trees. Planting trees in agricultural lands is relatively efficient and cost effective compared to other mitigation strategies, and provides a range of co-benefits important for improved farm family livelihoods and climate change adaptation.
Livestock improvements brought about by more research on ruminant animals, storage and capture technologies for manure and conversion of emissions into biogas are additional contributions that agriculture can make towards mitigating climate change. The anaerobic digestion of manure stored as a liquid or slurry can lower methane emissions and produce useful energy, while the composting solid manures can lower emissions and produce useful organic amendments for soils. To reach the full potential of agriculture in climate change mitigation, transformations are needed in both commercial and subsistence agricultural systems, but with significant differences in priorities and capacity.
In commercial systems, increasing efficiency and reducing emissions, as well as other negative environmental impacts, benefits by increasing carbon sinks, as well as reducing emissions per unit of agricultural product. The sustainable intensification of production, especially in developing countries, can ensure food security and contribute to mitigating climate change by reducing deforestation and the encroachment of agriculture into natural ecosystems. Mitigation of climate change through agriculture is an environmental service that smallholders can provide and is often synergistic with improvements to agricultural productivity and stability.
Climate smart agriculture as a way forward
Climate-smart agriculture is a practice that sustainably increases productivity, resilience (adaptation), reduces/removes GHGs (mitigation), and enhances achievement of national food security and development goals. Efficiency, resilience, adaptive capacity and mitigation potential of the production systems can be enhanced through improving its various components. The future of agricultural production relies on both designing new ways to adapt to the likely consequences of climate change, as well as changing agricultural practices to mitigate the cli-mate damage that current practices cause, all without undermining food security, rural development and livelihoods.
Major transformation of the agriculture sector will be necessary and this will require institutional and policy support. Better-aligned policy approaches across agricultural, environmental and financial boundaries and innovative institutional arrangements to promote their implementation is crucial. Enabling policy environment to promote climate-smart smallholder agricultural transformations is greater coherence, coordination and integration between climate change, agricultural development and food security policy processes.
In farm decision-making and practices, the adaptation and mitigation measures are often the same agricultural practices that also benefit farmers by increasing productivity and resilience. However, there may be important trade-offs too. In these situations, where climate-smart practices entail costs for the farmers and these changes are deemed to bring substantial benefits to the society, the farmers facing extra costs should be compensated through different payment mechanisms, rewarding these farmers for the environmental service they provide. With this prospect climate change creates new financing requirements both in terms of amounts and financial flows associated with needed investments, which will require innovative institutional solutions. In synthesizing potential synergies between adaptation and mitigation in smallholder agricultural transitions.