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difficult to project, anticipated climate change combined

with other drivers of change is likely to intensify current

agricultural water management challenges in India. Higher

temperatures and more frequent droughts are expected to

reduce water availability, hydropower potential and crop

productivity in general. The effects of population growth

and increasing water demand, which are often, but not

always, coupled, are likely to be a more significant source of

water stress than climate change when considering changes

to mean precipitation and run-off. Increasing temperatures

in all regions are expected to intensify evaporative demand,

which would tend to increase the amount of water required

to achieve a given level of plant production if crop phenol-

ogy and management are to be held constant. However, if

cultivars and planting dates were to remain unchanged,

accelerated crop development in response to temperature

increases would tend to have the opposite effect on water

requirements. Rising temperatures are also expected to

increase evaporative losses of surface water resources.

Future changes in potential evapotranspiration (PE)

over India and adjoining countries project an increase in

all the global climate models. In the monsoon season the

maximum increase in PE is over north-western India. The

interrelationship between PE and rainfall was assessed by

mapping the number of global climate model (GCM) exper-

iments which yield increased P/PE ratio for the monsoon

season. A number of GCMs agree that the P/PE ratio

becomes more favourable over north-eastern India and

that changes in this ratio are less favourable in the post-

monsoon season and in the extreme south in the country.

Presently, the India Meteorological Department has taken

up an extensive modernization programme to enhance

weather services in the country and for combating deser-

tification through the induction of advanced technology

for observational systems (including automatic weather

stations, Doppler weather radars, advanced satellites and

upper air observations network), installation of a central-

ized information processing system and its link with the

national meteorological centres. The outcomes of these

modernization programmes are district-level forecast

services, nowcasting of severe weather events, extended

range (10-20 days or a month) forecasting, increased

accuracy of short, medium and long-range forecasts, multi-

hazard early warning, real-time data availability, improved

spatial and temporal coverage and better service delivery.

Thus, it is advisable to focus on prevention of desertifi-

cation in dry farming tracts of India along with the other

regions. The following adaptation strategies are being

Calculated change (per cent) in mean seasonal PE for for 10C of global warming: (left) the Canadian Climate Centre

experiment and (right) the Geophysical Fluid Dynamics Laboratory experiment

Source: Chattopadhyay & Hulme, 1997

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