effect of climate change like delaying of monsoon, temperature change etc. on agriculture in india and west bengal

1. EFFECT OF CLIMATE CHANGE ON
AGRICULTURE
Climate change will have a profound impact on human and eco-systems during the coming
decades through variations in global average temperature and rainfall according to the
Fourth Assessment Report (FAR) of the Intergovernmental Panel on Climate Change
(IPCC). Agriculture and allied sectors are highly sensitive to climate change. The interaction
between agricultural performance and weather, which has been an important area of
research since the last few decades, has gained momentum due to the awareness of the
adverse effects of climate change on agriculture and livelihood.
Agricultural productivity is sensitive to two broad classes of climate-induced effects — (1)
direct effects from changes in temperature, precipitation, and carbon dioxide
concentrations (2) indirect effects through changes in soil moisture and the distribution
and frequency of infestation by pests and diseases.
Kavi Kumar and Parikh (1998) showed that the economic impact would be significant even
after accounting for farm-level adaptation. The loss in net revenue at the farm level is
estimated to be between 9 and 25 per cent for a 20C to 3.50C rise in temperature.
Ironically, West Bengal, Orissa and Andhra Pradesh are predicted to benefit – to a small
extent – from warming.
EFEECT ON WEST BENGAL
West Bengal is facing inadequate and erratic rainfall in successive years mainly in South
Bengal Districts. More than 80% of annual precipitation occurs during monsoon and that
too erratically in respect of time and space causing drought like situations in summer and
flood during monsoons destroying both summer and monsoon crops. The onset of
monsoon is delayed. There is an overall warming with minimum temperatures increasing
faster than the maximum temperatures. Cyclone frequency of severe cyclonic storms is
increasing over Bay of Bengal and the sea level is rising globally.
ERRATIC MONSOON
Onset of monsoon is getting delayed and monsoon precipitation has become very erratic. In
2008-09, a large part of the Gangetic West Bengal recorded heavy WEST BENGAL ACTION

2. PLAN ON CLIMATE CHANGE 61 to very heavy rainfall in the 1st half. As a result of this
downpour, accompanied by breaching of embankments of rivers traversing through these
regions, vast areas of Paschim and Purba Medinipur came under the grip of unprecedented
flood. Aman seedbeds, summer vegetables, jute, betel vine, flowers, etc. were damaged and
the entire farming community had to incur irreparable loss. In 2009-10, however, there
was shortage of rainfall, and a drought like situation was created, again leading to
reduction in productivity of most of the crops.
TEMPERATURE FACTOR
The minimum temperatures are increasing leading to increase in winter temperatures that
have begun to remain considerably above normal causing uncongenial situation for
cultivation of most of the Rabi crops. The rise in temperature during critical stages of wheat
is leading to less production. The production of other winter crops like pulses and oil -seeds
are also decreasing. The area under total pulses decreased again this year to 184 thousand
hectares from 200.9 thousand hectares during 2007-08.
Increasingly the duration of high temperatures during summer is extending, and in spite of
adequate rainfall, it is leading to reduced production of late-sown Boro paddy. As air
temperature is increasing, growth and multiplication of pests is taking place. Increase in
length of extreme temperature will decrease soil moisture affecting soil microbes
adversely.
ABOUT SUNDERBAN
One of the most vulnerable aspects of the Sunderban wetlands is its mangroves. Changes in
temperature and CO2 levels, changed rainfall patterns, frequency of storms, and rise in sea
level directly threaten the mangrove ecosystems and diminish their ability to cope with
changes. Ambient temperatures higher than 35°C will affect mangroves by reducing the
rate of leaf formation, ultimately causing the population to weaken. If temperatures rise
above 35°C, there will be acute thermal stress affecting the development of roots and seeds.
At temperatures of 38-40°C, photosynthesis will stop, killing the mangrove population. On
the other hand, if it gets cooler, which can also happen with climate change, mangroves
would be prevented from migrating north.