and by changing from urea to ammonium sulfate fertilizer, which impedes CH4 production (DeAngelo et al., 2005; Li et al., 2006). There is also potential to achieve CH4 reduction through integrating new insights of how the rice plant regulates CH4 production and transport into rice breeding programs (Wassmann and Aulakh, 2000; Kerchoechuen, 2005).
Emerging technologies that could provide future options for reducing CH4 and N2O emissions from livestock include: adding probiotics, yeasts, nitrification inhibitors, and edible oils to animal feed that reduce enteric CH4 and N2O emissions from livestock systems (Smith et al., 2007) and controlling methanogenic archae, microorganisms that live in the rumen and generate CH4 during their metabolism More extensive use of the antibiotic Rumensin® (monensin sodium), currently used to improve feed efficiency and prevent Coccidiosis, a parasitic intestinal infection, would improve energy utilization of feedstuffs through increased production of proprionic acid by rumen microorganisms and reduce the production of CH4. However, because Rumensin is also toxic to methanogenic bacteria, it should not be fed to cattle whose waste is to be used for CH4 generation.
Seeds. A viable option for small-scale production systems would be to refine and more widely disseminate the practice of adding small quantities of fertilizer to seed, such as through seed coating (Rebafka et al., 1993) or soaking/ priming (Harris, 2006) methods. Addition of fertilizer P and micronutrients to seed, rather than soil, is an inexpensive but highly effective means for improving plant nutrition and increasing yield (> 30% average yield increase reported) on drought-prone, acidic, low fertility soils. Seed priming with dilute fertilizer has average benefit/cost ratios 20 to 40 times greater than that achieved with fertilizer addition to the soil.
This is could be an effective strategy for small-scale systems, though there are several impediments such as low availability of quality fertilizer in local markets, lack of extension services for conveying technical information, and inability of farmer to pay for fertilizer-treated seed. Imbedding these technologies within larger efforts to overhaul the seed sector, which could include credit for purchasing improved seed and information about improved crop establishment practices could facilitate farmer adoption of these technologies. These technologies also could be disseminated into local communities by targeting farmers that have made prior land improvements to increase soil water retention, and may therefore be less risk adverse.
Water resources and fisheries. While the broad implications of climate change on marine systems are known—including rising sea levels, sea surface temperatures, and acidification—the degree and rate of change is not known, nor are the effects of these physical changes on ecosystem function and productivity (Behrenfeld et al., 2006). To adjust and cope with future climatic changes, a better understanding of how to predict the extent of change, apply adaptive management, and assign risk for management decisions is needed (Schneider, 2006).
To ensure the survival of many communities, their livelihoods and global food security, new approaches to monitoring, predicting, and adaptively responding to changes in |
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marine and terrestrial ecosystems need to be developed. Ecosystem resilience can be built into fisheries and essential fish habitats (including wetlands and estuaries) and approaches developed that reduce risk and ensure continuation of ecosystem goods and services (Philippart et al., 2007). Rising sea levels will alter coastal habitats and their future productivity, threatening some of the most productive fishing areas in the world. Changes in ocean temperatures will alter ocean currents and the distribution and ranges of marine animals, including fish populations (di Prisco and Verde, 2006; Lunde et al., 2006; Sabates et al., 2006; Clarke et al., 2007). Rising sea surface temperatures will result in additional coral reef bleaching and mortality (Donner et al., 2005). Rising atmospheric CO2 will lead to acidification of ocean waters and disrupt the ability of animals (such as corals, mollusks, plankton) to secrete calcareous skeletons, thus reducing their role in critical ecosystems and food webs (Royal Society, 2005).
Precautionary approaches to management of fish and freshwater resources are needed to reduce the impacts from climate change, including conserving riparian and coastal wetlands that can buffer changes in sea level rise and freshwater flows. Human-induced pressures on fish populations from overfishing must be reduced so that fish populations have a chance of withstanding the additional pressures from warming seas and changes in seasonal current patterns. Human demand for increasing freshwater supplies needs to be addressed through water conservation and water reuse, thus allowing environmental flows to maintain riparian and wetland ecosystems.
Small-scale fishers, who lack mobility and livelihood alternatives and are often the most dependent on specific fisheries, will suffer disproportionately from such large-scale climatic changes. In Asia, 1 billion people are estimated to be dependent upon coral reef fisheries as a major source of protein, yet coral reef ecosystems are among the most threatened by global climate change. The combined effects of sea surface temperature rise and oceanic acidification could mean that corals will begin to disappear from tropical reefs in just 50 years; poor, rural coastal communities in developing countries are at the greatest risk and will suffer the greatest consequences (Donner and Potere, 2007; www. icsf.net). Climate change is a major threat to critical coastal ecosystems such as the Nile, the Niger and other low-lying deltas, as well as oceanic islands which may be inundated by rising sea levels. The environmental and socioeconomic costs, especially to fisheries communities in developing countries, could be enormous.
Water related risk can be reduced through adaptation and adoption of strategies to improve water productivity in rainfed farming systems. These strategies entail shifting from passive to active water management in rainfed farming systems and include water harvesting systems for supplemental irrigation, small scale off-season irrigation combined with improved cropping system management, including use of water harvesting, minimum tillage and mulch systems, improved crop varieties, improved cropping patterns (Molden et al., 2007), and particularly mitigation of soil degradation (Bossio et al., 2007). These existing technologies allow active management of rainfall (green water), rather than only managing river flows (blue water) (Rockstrom et al., 2007). |