Genetically Improved Crops - The Oxford Topic of Food, Politics, and Society - page 67

freshwater use. The Stern Report (2006) underlines the decline of crop yields, ocean
acidification, poor plant nutrition and abiotic stress, population displacement, and
threatened ecosystems as effects of climate change. In addition, broader, more systemic
consequences of abiotic stresses such as drought beyond food insecurity are decreased
household income, the loss of assets due to slaughter of livestock, health threats due to
the lack of water for hygiene and household uses, environmental degradation, and less
sustainable land management (Watson, this volume). These effects must be considered
in the light of growing population levels. To feed the overall population the world will
have to double its rate of agricultural production over the next twenty-five years, despite
having already quadrupled it in the last fifty. It is estimated that only 10% of world's arable
land may be categorized as free from stress. The rapid change in environmental condi-
tions is likely to override the adaptive potential of plants. Such abnormal environmental
parameters include drought, salinity, cold and freezing, high temperatures, waterlog-
ging, high light intensity, ultraviolet radiation, nutrient imbalances, metal toxicities,
nutrient deficiencies and are collectively termed abiotic stress . Severe drought accounts
for half the world's food emergencies annually. In this context, solutions must be devel-
oped to adapt crops to existing but also evolving conditions such as marginal soils.
The agriculture sector is both a contributor to and provider of potential solutions
to increased abiotic stresses. It impacts two of the principal components of climate
change: greenhouse gases and water. Agriculture is a major source of greenhouse gas
emissions. Practices such as deforestation, cattle feedlots, and fertilizer use currently
account for about 25% of greenhouse gas emissions. When broken down, this amounts
to 14% of carbon dioxide emission, 48% of methane, and 52% of nitrous oxide emissions
(Stern Report 2006). In addition, agriculture uses a significant amount of fresh water;
approximately 70% of the water currently consumed by humans is used in agriculture,
and this is likely to increase as temperatures rise. The distributional impact will surely be
asymmetrical globally, with much greater impact on resource-poor farmers in poorer
nations.
Given the potential impacts of climate change on the range and extent of agricultural
productivity and the impact of agriculture practice itself on global warming, effective
technology should play a substantial part in mitigating climate change. This is especially
relevant in emerging countries where producers and consumers are more subject to
the vagaries of climate fluctuations than in the West, where there is greater capability
of responding to the effects and managing resources. Green biotechnology offers a set
of tools that can help producers limit greenhouse gas emissions as well as adapt their
agricultural techniques to shifting climates. Green biotechnology's three major contri-
butions toward mitigating the impact of climate change are greenhouse gas reduction,
crop adaptation and protection, and yield increase in less desirable and marginal soils.
The first of these issues is greenhouse gas reduction. In addition to carbon dioxide,
agriculture contributes two of the other major greenhouse gases; one of these, nitrous
oxide, has a global warming potential of about three hundred times that of carbon
dioxide. In addition, nitrous oxides stay in the atmosphere for a considerable period.
Nitrous oxide is produced through bacterial degradation of applied nitrogen fertilizer.