Impacts of Climate Change on Agriculture - Climate Resilient Agriculture for Ensuring Food Security - page 46

Europe is expected to grow up to 25 % in
optimum hydrological conditions.
More favorable effects on yield tend to
depend to a large extent on realization of the
potentially benefi cial effects of carbon dioxide
on crop growth and increase of effi ciency in
water use. Decrease in potential yields is likely
to be caused by shortening of the growing
period, decrease in water availability, and poor
vernalization.
Global climatic changes can affect agriculture
through their direct and indirect effects on the
crops, soils, livestock, and pests (Table 4.3 ).

Indirectly, there may be considerable effects on
land use due to snow melt, availability of irriga-
tion water, frequency and intensity of inter- and
intra-seasonal droughts and fl oods, soil organic
matter transformations, soil erosion, changes in
pest profi les, decline in arable areas due to sub-
mergence of coastal lands, and availability of
energy. Equally important determinants of food
supply are socioeconomic environment, includ-
ing government policies, capital availability,
prices and returns, infrastructure, land reforms,
and inter- and intranational trade that might be
affected by the climatic change.

Table 4.3 Potential impacts of climate change on different sectors of agriculture (Aggarwal et al. 2009a )
Sector Impact

Crop Increase in ambient CO 2 concentration is benefi cial since it leads to increased photosynthesis in several

crops, especially those with C3 mechanism of photosynthesis such as wheat and rice, and decreased
evaporative losses. Despite this, yields of major cereals crops, especially wheat, are likely to be reduced due
to decrease in grain-fi lling duration, increased respiration, and/or reduction in rainfall/irrigation supplies
Increase in extreme weather events such as fl oods, droughts, cyclones, and heat waves will adversely
affect agricultural productivity
Reduction in yields in the rainfed areas due to changes in rainfall pattern during monsoon season and
increased crop-water demand
Incidence of cold waves and frost events may decrease in future due to global warming, and it would lead
to a decreased probability of yield loss associated with frost damage in northern India in crops such as
mustard and vegetables
Quality of fruits, vegetables, tea, coffee, aromatic, and medicinal plants may be affected
Incidence of pest and diseases of crops to be altered because of more enhanced pathogen and vector
development, rapid pathogen transmission, and increased host susceptibility
Agricultural biodiversity is also threatened due to the decrease in rainfall and increase in temperature,
sea-level rise, and increased frequency and severity of droughts, cyclones, and fl oods

Water Demand for irrigation water would increase with rise in temperature and evapotranspiration rate. It may

result in lowering of groundwater table at some places
The melting of glaciers in the Himalayas will increase water availability in the Ganges, Brahmaputra, and
their tributaries in the short run, but in the long run, the availability of water will decrease considerably
A signifi cant increase in runoff is projected in the wet season that, however, may not be very benefi cial
unless storage infrastructure is vastly expanded. This additional water in the wet season, on the other
hand, may lead to increase in frequency and duration of fl oods
The water balance in different parts of the world will be disturbed, and the quality of groundwater along
the coastal track will be affected more due to intrusion of sea waters

Soil Organic matter content, which is already quite low in soils, would become still lower. Quality of soil

organic matter may be affected
The residues of crops under the elevated CO 2 concentrations will have higher C:N ratio, and this may
reduce their rate of decomposition and nutrient supply
Rise in soil temperature will increase N mineralization, but its availability may decrease due to increased
gaseous losses through processes such as volatilization and denitrifi cation
There may be a change in rainfall volume and frequency, and wind may alter the severity, frequency, and
extent of soil erosion
Rise in sea level may lead to saltwater ingression in the coastal lands, turning them less suitable for
conventional agriculture

(continued)