Adaptation to climate change is likely; the extent depends on the affordability of adaptive measures mentioned in Table 11.4, access to technology and biophysical constrains such as water resource availability, soil characteristics, genetic diversity, crop breeding, and topography. National studies have shown incremental additional costs of agricultural production under climate change which could create a serious burden for some developing countries (IPCC, 1996).
Nearly all agricultural impact studies conducted over the past 5 years have considered some technological options for adapting to climate change (IPCC, 1996). Technology transfer and diffusion of new technologies could in particular focus on improvement of irrigation technology and alternative species and varieties.
Improving irrigation technology.
Changes in temperature and precipitation levels will alter the hydrological cycle and water supplies. In general, the IPCC (1996) notes that estimated precipitation increases in high latitude regions may lead to runoff increase; runoff will tend to decrease in lower latitudes due to combined temperature increase and precipitation decrease. Increased rainfall intensity would increase soil erosion, while in other regions agriculture could be affected by drought. Rind et al. (1990) use GCM results to calculate that for many mid-latitude locations (e.g., USA) the incidence of severe droughts that currently occur only 5% of the time could rise to a 50% frequency by 2050, based on the difference between precipitation and potential evapotranspiration. Such a change would constitute a severe natural disaster for agricultural production.
About 253 million hectares, 17% of the world's crop land, are irrigated. This land produces more than one-third of the world's food (Geijer et al., 1996). Irrigation is therefore increasingly important for adapting to the effects of climate change on agricultural production. Almost three-quarters of the world's irrigated area is in developing countries. To mitigate the negative effects of climate change on agriculture, developing countries should improve their existing irrigation efficiency through adoption of drip irrigation systems and other water-conserving technologies (FAO 1989, 1990a). An alternative is to import technologies and equipment from developed countries that have advanced irrigation technologies. See Box 11.6 for a discussion of the main barriers involved.
|Box 11.6 Irrigation Technology Transfer between Countries and across Barriers|
The main flow of irrigation technology transfer is from developed to developing countries. The primary barrier encountered by the importing developing countries is that they cannot afford the high cost of patents and equipment. The second barrier is that the importers do not have enough money to build the auxiliary equipment for the introduced technology, because developing countries, in many cases, only buy key equipment due to their limited financial resources. The third barrier for irrigation technology transfer between countries is that the importing developing countries are not clearly aware of what technologies fit their conditions and where they can find the suitable ones. The importers do not always receive satisfactory service when there are problems with their imported equipment or scientific instrument.
New species and varieties adapted to changing climate.
For most major crops, varieties exist with a wide range of maturities and climatic tolerances. For example, Matthews et al. (1994) identified wide genetic variability among rice varieties as a reasonably uncomplicated response to spikelet sterility in rice that occurred in simulations for South and Southeast Asia. Studies in Australia showed that responses to climate change are strongly cultivar dependent (Wang et al., 1992). The genetic base is broad for most crops but limited for some (e.g., kiwi fruit). A study by Easterling et al. (1993) explored how hypothetical new varieties would respond to climate change (also reported in McKenney et al., 1992). Heat, drought, and pest resistance, salt tolerance, and general improvements in crop yield and quality would be beneficial for crop adaptation (Smit, 1993). See Box 11.7.
|Box 11.7 New Rice in Sierra Leone|
The development of a new mangrove rice variety in Africa is an important case study of technology development and transfer. Much of the success of this effort hinged on the accident of a critical mass of researchers at the government rice research station in Rokupr Sierra Leone and the interest of the West African Rice Research Development Association (WARDA) in this effort. WARDA provided additional resources to the station at Rokupr to carry out the development of a new rice variety to meet the changed climate conditions, and improve yields above those previously achieved. The Sierra Leone agricultural research establishment was able to demonstrate the value of their rice research effort to the food supply of the nation and WARDA was able to demonstrate to their financial supporters their value in contributing to this new technology and its transfer. There was a German seed distribution project that helped with some seed distribution, but farmers themselves undertook most of the technology transfer to other farmers once the success of the new variety became apparent (Prahah-Asante et al., 1982, 1986; Spencer, 1975; Spencer et al., 1979; Tre et al., 1998; WARDA, 1987; Zinnah, 1992; Zinnah et al., 1993).
Most developing countries depend heavily on agriculture. Developing countries are barely able to adopt the mitigation technologies mentioned in Table 11.3 to mitigate the GHG emissions in agricultural systems, because of barriers mentioned in Table 11.4. If advanced technologies are transferred to them with demonstration projects, as well as technical assistance and financial support, GHG emissions will be reduced.
Improvement of the efficiency of nitrogen fertiliser.
Nitrogen fertiliser efficiency decreased with increased nitrogen fertiliser input. So farmers need additional information such as soil testing data, as well as educational support to interpret the data. They can also gain experience by participating in demonstration projects. Extension personnel are needed to provide on-farm technical assistance with new practices to increase N efficiency. Availability of application machinery and technologies must be transferred simultaneously to be effective.
Reducing methane emission from rice fields.
Feasible mitigation strategies that have been verified to significantly reduce methane emission from rice fields are temporary midseason aeration of the soil, using fermented instead of fresh organic manure, applying sulfate containing fertiliser, and planting/breeding rice cultivars with low emission capacity.
Reducing methane emission from animal waste.
Biogas digesters can provide clean energy and high quality fertiliser, and can be an important option for reducing methane emission from livestock manure. This technology is widely recognised as an EST and has been widely accepted all over the world, especially in China and India.
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