Agriculture Reference
In-Depth Information
the recent past different parts of the world offered a glimpse of the chal-
lenges climate change would bring. Analysis of recorded climatic datasets
clearly indicates that there has been a 0.3 °C to 0.6 °C warming of earth
surface since the late nineteenth century. The average global temperature
has increased by 0.8 °C in the past 100 years and is expected to rise by
1.8 °C to 4.0 °C by the year 2100. For Indian region (South Asia), the
Intergovernmental Panel on Climate Change (IPCC) has predicted 0.5 to
1.2 °C rise in temperature by 2020, 0.88 to 3.16 °C by 2050 and 1.56
to 5.44 °C by 2080, depending on the scenario of future development.
The atmospheric warming will also be associated with changes with rain-
fall patterns, increased frequency of extreme events of drought, frost and
flooding. Since the late 1970s, there have been increases in the percentage
of the globe experiencing extreme drought or extreme moisture surplus.
The Intergovernmental Panel on Climate Change (IPCC) predicts that
by 2050, mean temperatures around the planet may rise by between 2 and
5 °C or more and atmospheric CO 2 concentration are likely to be >550
ppm (cf. 380 ppm at present). Tropical and semitropical climates in par-
ticular are expected to experience dramatic increases in temperatures, as
well as more variable rainfall (Jarvis et al., 2010). Of serious concern is the
fact that most of the world's low-income families dependent on agriculture
live in vulnerable areas, namely in Asia and Africa. Farmers having small
land holdings in India will need to adapt to higher temperatures and shift-
ing precipitation patterns. In addition, climate variability will likely cut
into global food production, exacerbating the existing problems of pov-
erty, food insecurity, and malnutrition. Furthermore, the greenhouse gas
emissions are once again rising rapidly, making the climate change chal-
lenge to food security much greater.
In general, alterations in our climate are governed by a complex system
of atmospheric and oceanic processes and their interactions. In the con-
text of crop production, relevant atmospheric processes consist of losses
in beneficial stratospheric ozone (O 3 ) concentration and increasing con-
centrations of the surface-layer trace gases, including atmospheric carbon
dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O) and sulfur dioxide
(SO 2 ). Surface level O 3 ; SO 2 ; and CO 2 have direct impacts on crops, while
CO 2 , CH 4 and N 2 O are critical in altering air temperature.
Particular attention is paid to likely changes on extreme events and sea
level alterations. It is reported with high to very high confidence that in
the 1990-2100 periods most extreme events will increase in intensity
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