Geoscience Reference
In-Depth Information
intra-seasonal droughts and floods, soil organic matter trans-
formations, soil erosion, change in pest profiles, decline in
arable areas due to submergence of coastal lands and avail-
ability of energy. All these can have a tremendous impact on
agricultural production and, hence, food security of any region
(Aggarwal, 2003). The rising temperatures and CO
2
and uncer-
tainties in rainfall associated with global warming may or
may not have serious direct and indirect consequences on crop
production. It is, therefore, important to have an assessment of
these consequences of global warming on different crops, espe-
cially on cereals contributing to food security (Gadgil, 1995;
Gadgil et al., 1999a,b). Mechanistic crop growth models are
now routinely used for assessing the impacts of climate change.
There are several crop models now available for the same crop
that can be employed for impact assessment of climate change
(Mall and Aggarwal, 2002). Crop models, in general, integrate
current knowledge from various disciplines, including agrome-
teorology, soil physics, soil chemistry, crop physiology, plant
breeding and agronomy, into a set of mathematical equations to
predict growth, development and yield of a crop (Aggarwal and
Kalra, 1994; Hoogenboom, 2000).
As there is an intimate relationship between occurrence
and distribution of pests and diseases and the temperature, any
change in temperature will have a significant effect on pest and
disease development and their interaction with agricultural
crops. A number of effects of global warming on insects, pests
and disease-causing organisms have been identified. These are
increases in the number and rate of development in a season,
expansion of area of distribution, earlier establishment in their
population in a favourable season, and more intense attacks,
particularly by midnight and exotic species. Again, with the
shifting agricultural production to new areas and changing of
the agro-climatic regions, the emergence of new insect species
is very possible which will render an additional threat to agri-
cultural production.
15.8
Climate change and water availability
Climate change is likely to intensify, accelerate or enhance the
global hydrological cycle (IPCC, 2008). Water is the primary
medium through which climate change influences the Earth's
ecosystem and maintains the livelihood and well-being of soci-
eties. Temperature change due to global warming influences
the availability of water. Higher temperatures and changes in
