Agriculture Reference
In-Depth Information
21.1 INTRODUCTION
Day to day variation in the state of our atmosphere is called weather. Aver-
age state of the weather that is fairly stable and predictable is called cli-
mate. Climatic parameters include temperature, amount of precipitation,
days of sunlight, humidity and wind, etc. Climate change refers to varia-
tion in earth's global climate or regional climate over different timescales.
Climate change was happening from time immemorial, but the accelerated
changes due to anthropogenic factors and consequent global warming is of
serious concern. Global warming due to accumulation of different green
house gases is not only indicated by changes in temperature but, represents
a series of events, which ultimately can have more implications than can't
be summarized in a few words. Major vulnerable areas as identified by
IPCC, covering almost every aspect of our life, are global social systems,
global biological systems and geophysical systems.
Anthropogenic activities have caused accumulation of Green House
Gases (GHG) in the atmosphere, leading to the potential hazards of cli-
mate change looming over us. The atmospheric concentration of CO
2
has
increased from the preindustrial levels of 280 ppm to 379 ppm in 2005
(IPCC, 2007). High carbon dioxide and other green house gases in the
atmosphere tend to warm up the atmosphere, besides affecting other me-
teorological variables. Long-term weather trends indicate constant rise in
temperature with increasing concentrations of GHG's mainly carbon diox-
ide, methane, oxides of nitrogen, etc. in the atmosphere. In
India 0.68°C
increase per century, increasing trends in annual mean temperature, warm-
ing more pronounced during post monsoon and winter, increase in ex-
treme rains in north-west during summer monsoon in recent decades and
lower number of rainy days along east coast was reported.
Agriculture sector, whether in developing or developed countries, de-
pends on climate and climatic resources leading to the development of
special consideration for this sector to study the impacts of climate change
among researchers. Intergovernmental Panel on Climate Change (IPCC)
and other researchers have stressed the need to study impacts on agricul-
tural production at local, regional, national as well as on global scales to
capture the local conditions. Projecting future crop yields has significant
uncertainty attached due to changed fertilizer and water application strate-
gies, occurrence of extreme climatic events, changes in pest and disease
occurrence. Decision Support Systems (DSS) or Crop Models provide a
