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Impact of Climate Change on Water Resources


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Title: Impact of Climate Change on Water Resources

Presentation on
Course No. PP- 605
Presented By TARU ANIL SAHEBRAO Ph.D. Fruit
Science. Reg. No-12/61
  • Submitted to,
  • Dr. R. S. Wagh
  • Associate Professor,
  • Department of Agril. Botany,
  • PGI, MPKV, Rahuri

Climate Change
United Nations Framework Convention on Climate
Change (UNFCCC) defines climate change as a
change of climate which is attributed directly or
indirectly to human activities that alters the
composition of the global atmosphere and which is
in addition to natural climate variability
observed over comparable time periods General
Definition Any systematic change in the
long-term statistics of climate elements (such as
temperature, pressure, or winds) sustained over
several decades or longer.
Drivers of change
River flows groundwater quality
Population demand for water
Wealth equity access
Impacts of Climate Change in Relation to Water
  • Air and Water Temperature Increases
  • Changing Rainfall Patterns
  • Droughts
  • Groundwater
  • Glacier Melt
  • Sea level rise
  • Agriculture and food security
  • Water Security
  • Health

Air and Water Temperature Increases
  • Temperatures are changing in the lower
    atmospherefrom the Earths surface all the way
    through the stratosphere (EPA 2007b). Most
    climate change scenarios project that greenhouse
    gas concentrations will increase through 2100
    with a continued increase in average global
    temperatures (IPCC 2007a, as found in EPA 2007c).
  • The average surface temperature of the Earth is
    likely to increase by (1.1 to 6.4C) by the end
    of the 21st century, relative to 1980-1990, with
    a best estimate of (1.8 to 4.0C).
  • The average rate of warming over each inhabited
    continent is very likely to be at least twice as
    large as that experienced during the 20th century
    (IPCC 2007a).

Changing Rainfall Patterns
  • A decline in monsoon rainfall since the 1950s has
    already been observed.
  • The frequency of heavy rainfall events has also
  • A 2C rise in the worlds average temperatures
    will make Indias summer monsoon highly
  • At 4C warming, an extremely wet monsoon that
    currently has a chance of occurring only once in
    100 years is projected to occur every 10 years by
    the end of the century.

Fig. Rainfall During the year 2007-2011
  • Evidence indicates that parts of South Asia have
    become drier since the 1970s with an increase in
    the number of droughts.
  • Droughts have major consequences, in 1987 and
    2002-2003, droughts affected more than half of
    Indias crop area and lead to a huge fall in crop
  • Droughts are expected to be more frequent in some
    areas, especially in north-western India,
    Jharkhand, Orissa and Chhattisgarh. Crop yields
    are expected to fall significantly because of
    extreme heat by the 2040s.
  • Investments in RD for the development of
    drought-resistant crops can help reduce some of
    the negative impacts.

  • More than 60 of Indias agriculture is rain-fed,
    making the country highly dependent on
  • Even without climate change, 15 of Indias
    groundwater resources are overexploited.
  • Although it is difficult to predict future ground
    water levels, falling water tables can be
    expected to reduce further on account of
    increasing demand for water from a growing
    population, more affluent life styles, as well as
    from the services sector and industry.

Glacier Melt
  • Glaciers in the northwestern Himalayas and in the
    Karakoram range - where westerly winter winds are
    the major source of moisture - have remained
    stable or even advanced.
  • On the other hand, most Himalayan glaciers -
    where a substantial part of the moisture is
    supplied by the summer monsoon - have been
    retreating over the past century.
  • At 2.5C warming, melting glaciers and the loss
    of snow cover over the Himalayas are expected to
    threaten the stability and reliability of
    northern Indias primarily glacier-fed rivers,
    particularly the Indus and the Brahmaputra. The
    Gangas will be less dependent on melt water due
    to high annual rainfall downstream during the
    monsoon season.

Sea level rise
  • Mumbai has the worlds largest population exposed
    to coastal flooding, with large parts of the city
    built on reclaimed land, below the high-tide
    mark. Rapid and unplanned urbanization further
    increases the risks of sea water intrusion.
  • With India close to the equator, the
    sub-continent would see much higher rises in sea
    levels than higher latitudes.
  • Sea-level rise and storm surges would lead to
    saltwater intrusion in the coastal areas,
    impacting agriculture, degrading groundwater
    quality, contaminating drinking water, and
    possibly causing a rise in diarrhea cases and
    cholera outbreaks, as the cholera bacterium
    survives longer in saline water.

Agriculture and food security
  • Even without climate change, world food prices
    are expected to increase due to growing
    populations and rising incomes, as well as a
    greater demand for biofuels.
  • Rice While overall rice yields have increased,
    rising temperatures with lower rainfall at the
    end of the growing season have caused a
    significant loss in Indias rice production.
    Without climate change, average rice yields could
    have been almost 6 higher.
  • Wheat Recent studies shows that wheat yields
    peaked in India and Bangladesh around 2001 and
    have not increased since despite increasing
    fertilizer applications. Observations show that
    extremely high temperatures in northern India -
    above 34C - have had a substantial negative
    effect on wheat yields, and rising temperatures
    can only aggravate the situation.

  • Seasonal water scarcity, rising temperatures, and
    intrusion of sea water would threaten crop
    yields, jeopardizing the countrys food security.
  • Should current trends persist, substantial yield
    reductions in both rice and wheat can be expected
    in the near and medium term. Under 2C warming by
    the 2050s, the country may need to import more
    than twice the amount of food-grain than would be
    required without climate change.
  • Crop diversification, more efficient water use,
    and improved soil management practices, together
    with the development of drought-resistant crops
    can help reduce some of the negative impacts.

Water Security
  • Many parts of India are already experiencing
    water stress. Even without climate change,
    satisfying future demand for water will be a
    major challenge. Urbanization, population growth,
    economic development, and increasing demand for
    water from agriculture and industry are likely to
    aggravate the situation further.
  • An increase in variability of monsoon rainfall is
    expected to increase water shortages in some
    areas. Studies have found that the threat to
    water security is very high over central India,
    along the mountain ranges of the Western Ghats,
    and in Indias northeastern states.

  • Climate change is expected to have major health
    impacts in India- increasing malnutrition and
    related health disorders such as child stunting -
    with the poor likely to be affected most
    severely. Child stunting is projected to increase
    by 35 by 2050 compared to a scenario without
    climate change.
  • Malaria and other vector-borne diseases, along
    with and diarrheal infections which are a major
    cause of child mortality, are likely to spread
    into areas where colder temperatures had
    previously limited transmission.
  • Heat waves are likely to result in a very
    substantial rise in mortality and death, and
    injuries from extreme weather events are likely
    to increase.
  • 5 million people mainly children die every
    year from preventable, water-related disease is
    surely one of the great tragedies of our time.
  • over 34 million people might perish in the next
    20 years from water-related disease

Review Articles
Water resources and climate change An Indian
perspective In recent times, several studies
around the globe show that climatic change is
likely to impact significantly upon freshwater
resources availability. In India, demand for
water has already increased manifold over the
years due to urbanization, agriculture expansion,
increasing population, rapid industrialization
and economic development. At present, changes in
cropping pattern and land-use pattern,
over-exploitation of water storage and changes in
irrigation and drainage are modifying the
hydrological cycle in many climate regions and
river basins of India. An assessment of the
availability of water resources in the context of
future national requirements and expected impacts
of climate change and its variability is critical
for relevant national and regional long-term
development strategies and sustainable
development. Sustainable development of surface
water and groundwater resources within the
constraints imposed by climate change and future
research needs in India. (Mall-2006)
What can be done
  • The development of indicators of climate change
    impacts on freshwater, and operational systems to
    monitor them
  • Impact studies of climate change at the monthly
    or higher temporal resolution scale is desirable
    rather than only on annual scale
  • The efficient use of ground water resources will
    need to be incentivized.
  • Develop local scale data sets and simple
    climate-linked computerized watershed models.
  • Adaptation processes and methods which can be
    usefully implemented in the absence of accurate
    projections, such as improved water-use
    efficiency and water-demand management, offer
    no-regrets options to cope with climate change.

  • An integrated approach is needed, given the
    diversity of interests to arrive at sustainable
  • RD studies are needed for the identified thrust
    areas under National Water Mission to achieve the
    envisaged objectives and goals.
  • Improvements in irrigation systems, water
    harvesting techniques, and more-efficient
    agricultural water management can offset some of
    these risks.