Introduction - Climate Resilient Agriculture for Ensuring Food Security - page 9

Table 1.1 Abundance and lifetime of greenhouse gases in the atmosphere
Parameters

CO 2 CH 4 N 2 O

Chlorofl uorocarbons

Average concentration 100 years ago (ppbV) 290,000 900 270 0

Current concentration (ppbV) (2007) 380,000 1,774 319 3-5

Projected concentration in the year 2030 (ppbV) 400,000-500,000 2,800-3,000 400-500 3-6

Atmospheric lifetime (year) 5-200 9-15 114 75

Global warming potential (100 years relative to CO 2 ) 1 25 298 4,750-10,900

Source: IPCC ( 2007 )

GHGs trap the outgoing infrared radiations from
the earth's surface and thus raise the temperature
of the atmosphere. The global mean annual tem-
perature at the end of the twentieth century, as a
result of GHG accumulation in the atmosphere,
has increased by 0.4-0.7 °C above that recorded
at the end of the nineteenth century. The past 50
years have shown an increasing trend in tempera-
ture at 0.13 °C per decade, while the rise in tem-
perature during the past one and half decades has
been much higher. The Intergovernmental Panel
on Climate Change has projected the temperature
increase to be between 1.1 and 6.4 °C by the end
of the twenty-fi rst century (IPCC 2007 ). Global
warming is expected to lead to other regional and
global changes in the climate-related parameters
such as rainfall, soil moisture, and sea level.
Snow cover is also reported to be gradually
decreasing. Therefore, concerted efforts are
required for mitigation and adaptation to reduce
the vulnerability of agriculture to the adverse
impacts of climate change and making it more
resilient.
The fourth assessment report of the IPCC
indicates that agriculture will be affected both by
long-term trends in mean temperature, precipita-
tion, and winds and by increasing climate vari-
ability, associated with greater frequency and
severity of extreme events such as droughts and
fl oods. Changes in the hydrological cycle will
affect agriculture in general and food production
specifi cally. Changing wind speeds and directions
will also affect crop and animal productivity.
At least 22 % of the area under the most
important crops in the world is expected to suffer
negative impacts from climate change by 2050.
In sub-Saharan Africa and Asia, 56 % and 21 %
of crops, respectively, are expected to be nega-

tively affected. Impacts on livestock production
are likely to be both direct, for example, produc-
tivity losses (physiological stress) owing to tem-
perature increases, and indirect, for example,
changes in the availability, quality, and prices of
inputs such as fodder, energy, disease manage-
ment, housing, and water. The distribution and
virulence of pests and diseases of crops and live-
stock will change. New equilibrium in crop-
pest-pesticide interactions will affect crop
production. Changes in agrobiodiversity will
have impacts, for example, on pollination. Crops
in some areas may benefi t from carbon fertiliza-
tion, though evidence from fi eld trials suggests
yield effects may be lower than hoped. Climate
change will also have impacts on the effective-
ness of irrigation, nutritional value of foods, and
safety in food storage and distribution.
The ability of most rural and urban communi-
ties to cope and adapt when confronted with eco-
nomic and social shocks and changes is high, but
needs ongoing, robust support. With increasing
climate variability and shocks to agricultural
food production, there are added disincentives
for farmers to reinvest. Over time, this might lead
to cumulative reductions in income and food
security. Lack of reinvestment can diminish
farmers', communities', and governments' abili-
ties to meet the threshold levels of capital needed
to transform farming systems in response to long-
term climate shifts, for example, to change from
a rice system to wheat or small grains. The com-
bination of failing household risk management
and failure to adapt to progressive climate change
might entrench poverty traps and food insecurity.
Farming systems and farmers will differ enor-
mously in their capacities to respond to climate
change. Differentiated adaptation strategies and