Geoscience Reference
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daily temperature in the range of 20-30°C. The impact of
climate change on rice production is of paramount importance
in planning strategies to meet the increasing demands for rice.
In recent years, controlled environment studies have enriched
our knowledge on the effects of increased temperature and
CO 2 level (Cure and Acock, 1986). This is mainly through the
stimulation of photosynthesis in the plant and improvement of
water use efficiency. The impact of temperature is more com-
plex, with the yield being reduced in both sides of the spectrum.
Most present varieties are highly sensitive to daytime tempera-
tures with yield decreasing linearly with increases in daytime
temperatures above 33°C (Satake and Yoshida, 1978). Jagadish
et al. (2007) showed that high temperatures affect the pattern
of flowering and the number of spikelets that reach anthesis in
rice. A reduction of the rice-growing areas is a possibility if
spikelet sterility would increase under predicted higher tem-
peratures and if water reserves could not meet the increased
evapo-transpiration. However, Bachelete and Kropff (1995)
predicted a significant increase in the irrigated ecosystem in
eastern India based on a modelling study on the impact of cli-
matic change on agro-climatic zones in Asia.
Agriculture is likely to respond initially to climate change
through a series of automatic mechanisms. Some of these
mechanisms are biological, and others are routine adjustments
by farmers and markets. Climate change will impact agricul-
ture by causing damage and gain at scales ranging from indi-
vidual plants or animals to global trade networks. At the plant
or field scale, climate change is likely to interact with rising
CO 2 concentrations and other environmental changes to affect
crop and animal physiology. Climate change involving altera-
tions in temperature, precipitation and sea level as well as
increased incidence of ultraviolet B radiation (280-320 nm) are
distinct possibilities in the not too distant future. Impacts and
adaptation (agronomic and economic) are likely to extend to the
farm and surrounding regional scales. As the Indian economy
depends to a great extent on agriculture, the assessment of cli-
mate change impacts on agriculture has acquired special signif-
icance. In developing countries such as India, climate change
could represent an additional stress on ecological and socio-
economic systems that are already facing tremendous pressures
due to rapid urbanisation, industrialisation and economic devel-
opment. With its huge and growing population, a 7500-km-long
densely populated (DOD, 2002) and low-lying coastline, and an
economy that is closely tied to its natural resource base, India is
considerably vulnerable to the impacts of climate change.
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