Authored by H.E. Luis Felipe Arauz Cavallini, Minister of Agriculture and Livestock, Costa Rica
Sustainable development is a planetary aspiration that the United Nations has outlined in 17 interrelated goals. Achievement of two of these goals, Goal 2: Zero Hunger and Goal 13: Climate Action depends on the dynamic and complex relation between agriculture and climate change. To fully appreciate this relationship, we need to understand that food security depends on food availability (i.e. production), access to food (related to poverty), and food utilization (related to human health), all of which are influenced by climate change. We also need to realize that agriculture has a three-fold relationship with climate change. Agriculture is a victim of the negative effects of climate change on productivity, while it is at the same time a contributor to CC through production of greenhouse gases, yet agriculture can provide solutions for CC through the multiple possibilities to mitigate GHG and slow down global warming.
Agriculture must continue to be productive, to feed the world and to foster prosperity in rural areas. It must become climate resilient in order to adapt to climate-change related perturbations. It needs to mitigate by sequestering carbon and/or reducing GHG production by agriculture and related activities, not only as a moral imperative and a world commitment, but because the less we mitigate, the more difficult it becomes to adapt.
Climate smart agriculture, an approach put forward by the United Nations Food and Agriculture Organization (FAO), refers exactly to this concept: agriculture that is productive, resilient and capable of mitigating greenhouse gases.The key to achieving these three objectives lies in the word “smart”, which must be understood as “knowledge-based”. Whether it is scientific or traditional knowledge, climate smart agriculture requires agro-ecological knowledge in its broadest sense. This knowledge must come from an understanding of how agro-ecosystems work and how processes relate to each other to bring about new processes related to system resilience and productivity, such as nutrient cycling, carbon sequestration in soil and root health. Clearly, the basis for climate-smart agriculture is also the basis of sustainability in agriculture. This holistic approach results in enhanced biodiversity, better roots and plant health, less need for chemical inputs, and other benefits associated with sustainable agricultural production. Two relevant questions in this context are: How do these principles apply specifically to climate change mitigation? How does climate change mitigation relate to sustainability in its environmental, social and economic dimensions?
Agriculture contributes to global warming through the production of greenhouse gases, primarily nitrous oxide (N2O) and methane. Nitrous oxide has a global warming potential 310 times of that of carbon dioxide, while the global warming potential of methane is 21 times higher than carbon dioxide. Strategies for climate change mitigation include both reduction of emissions of GHG and formation of carbon sinks for sequestering atmospheric carbon.
From an agro-ecological perspective, the production of GHG in agriculture results directly or indirectly from the inefficient use of inputs to the system.For example, the N2O produced in agriculture is often related to the excessive use of nitrogen fertilizer and represents nitrogen that was not incorporated into the protein necessary for plant and animal growth, production and nutritional value. The inefficient use of this input translates into economic losses through higher production costs, environmental damage from groundwater pollution, and contributes to CC through the release to the atmosphere of N2O.
Methane emissions from livestock are affected by feed quality and intake and represent carbon that did not contribute to animal growth and productivity. Inefficient water management in rice cultivation leads to the anaerobic conditions that result in methane production in flooded rice fields.
One approach to reducing GHG production in agriculture is to identify and correct these inefficiencies so that losses of C and N are minimized. Reducing GHG emissions through more efficient use of resources often has the added benefits of increased productivity or reduced costs, or both. Climate-smart agriculture is then eco-efficient agriculture.
In addition to reducing GHG production in agro-ecosystems, climate change mitigation can be achieved through carbon dioxide sequestration in biomass and in soil. Increasing the number of trees within agro-ecosystems (agro-forestry systems) or in the landscape where agriculture is practiced is a very effective mitigation practice. Given the right combination and arrangement of trees, crops and pastures, this practice can bring additional benefits such as nitrogen fixation, increased biodiversity, water conservation, and better animal productivity because of shade and nutritional supplementation. Forest areas in landscapes also buffer impacts of extreme weather, mitigating flooding and soil erosion, and aiding in water conservation during dry periods.
Recently, the carbon sequestration potential of soil and its crucial role in climate change mitigation have been recognized. Plant covers on soil (cover crops, improved pastures for example) can sequester large amounts of carbon in soil organic matter. Restoration of degraded land is essential to enhancing carbon sequestration in soils. The 4x1000 initiative promoted by France is a very important step towards GHG mitigation by means of soil carbon sequestration.
Many agricultural practices which aid in GHG mitigation also help in climate change adaptation, as seen in the following examples. There are numerous other examples in animal production systems, perennial cropping systems, annual arable crops and vegetable production, but we need to keep in mind that there is no universal prescription. There is no one-size-fits-all solution. Every system is different, every region is different, but what all solutions have in common is that they should be based on agro-ecological principles.
Rice: It is a well established fact that paddy rice is more productive than upland rain-fed rice, but the anaerobic conditions in paddy rice result in high methane production. A growing body of scientific research is showing that efficient use of water, which is an adaptation practice especially in areas where reduced water availability is anticipated, can reduce methane production without reducing yields. Also, optimization of fertilization application can reduce N2O production and increase yields in irrigated rice.
Tomato: Research conducted in California by Taryn Kennedy, Emma Suddick and Johan Six showed that tomato grown in an “integrated” system (drip irrigation and fertigation) yielded more, produced less N2O and used less water compared with tomato grown under “conventional” conditions (furrow irrigation and sidedress fertilizer injection.
Coffee: The aim of the coffee NAMA project in Costa Rica is low carbon emission coffee production. Carbon sequestration by shade trees and reduction of N2O emissions from soil through optimization of fertilizer applications are two key components of the coffee NAMA project. The use of shade trees in coffee plantations provides long-term benefits in productivity and quality and also contributes to adaptation by enhancing soil and water conservation. Conversion of waste products into energy through gasification is another key component for reducing methane emissions. With these practices, reduction of GHG plus economic benefits through reduced costs and increased productivity are expected.
Cattle: Low-carbon livestock production is also being implemented in Costa Rica. Key components are rotational grazing, live fences, improved pastures and better timing of fertilizer application. These practices are expected to reduce GHG production in soil and increase carbon capture in soil and tree biomass. Increased animal density and healthier pastures should lead to increased productivity and a reduction in methane production from enteric fermentation. The adaptation benefit of lower temperatures under shade will also help increase productivity by reducing thermal stress of the animals.
In conclusion, the three objectives of climate-smart agriculture, mitigation, adaptation and productivity, can be obtained simultaneously. To achieve this, an agro-ecological approach that considers multiple interactions within agro-ecosystems or at the landscape level is necessary. As we understand these interactions, climate smart practices can be devised. To do so we need to move from input-intensive to knowledge-intensive agriculture.It is not easy, but it is the intelligent, responsible and ethical way.