Climate Change and Agriculture - The Oxford Topic of Food, Politics, and Society - page 457

food production and environmental sustainability. Rice production in China leads
to soil erosion, damage of forest ecosystems, and degradation of grassland, causing
between $9.8 and $21.2 billion of damage in 1990 alone (Smil, 1997). Two-thirds of tropi-
cal deforestation is done to prepare land for agriculture, nearly half of which degrades
to only half its initial quality within three years (Pinstrup-Andersen and Pandya-Lorch,
1994). That land then quickly moves from forest to farm to livestock pasture. However,
agricultural intensification does not necessarily, as often claimed, reduce environmental
quality (Pinstrup-Andersen and Pandya-Lorch 1994; Lee and Barrett 2001; Bouwman,
et al. 2011). Rather, input mismanagement both harms the environment and reduces
farming efficiency; overgrazing, erosion, poor irrigation processes, and excessive, insuf-
ficient, or poorly timed fertilizer and pesticide applications are the problem, not these
resources' proper usage.
Steady, reliable, clean sources of water are essential for the food system. Ground and
surface water depletion (partially caused by agricultural mismanagement) and chang-
ing rainfall patterns discussed earlier are significant binding constraints, particularly
where irrigation has not been properly developed. IPCC (2007) predicts that nearly half
the world's current population could face a shortage of clean water by 2080, whereas
the Bonn Declaration (GWSP, 2013) warns that more than half will face a severe water
shortage within a generation. Most fresh water is consumed by agriculture. However,
use efficiency is generally low and significant amounts evaporate or leak from poorly
maintained irrigation channels. Obtaining more food from less water is essential to feed
growing global and local populations without depleting or harming water resources.
This challenge is exacerbated by the growth of demand for livestock, which consumed
8 percent of all fresh water in 2000 and is expected to reach 16 percent by 2050 (Steinfeld
et al. 2006; see also Mehta-Bhatt and Ficarelli, this volume). The uncertainties about
how climate change will affect future rainfall patterns make this challenge even greater.
These inefficiencies stem in large measure from a failure to internalize the social value
of water in private costs and large public water subsidies. When farmers are forced to
pay the same market prices for irrigation water as industry and housing, they invest in
techniques that increase water-use efficiency. These include drip irrigation, consistent
irrigation channel maintenance, and mulch layers or zero tillage that reduce evapo-
ration and soil erosion while improving water saturation and carbon sequestration.
Brown (2009) discusses successful initiatives in India and Mexico that devolved control
of water resources to local farmers associations. Although local farmers bore the costs of
their own water use, the gains from greater control and management of those resources
were greater.
Each of these impacts from agriculture to poverty and climate change is more
amenable to public policies of specific national governments than is mitigation of
global climate change. Responding to these pressures through smart investments
in agriculture will be part of a package of responses to help poor farmers adapt to
climate change and escape poverty (ILO, 2005; World Bank, 2007; IPCC 2012;
Pinstrup-Andersen and Watson 2011). With most poor people in rural areas, increas-
ing food access, farm incomes, and labor productivity can have a significant impact