Transcript Chapter 4: Emerging Water Shortages

Chapter 4: Emerging Water
Shortages
By Cody McNutt and Jennifer Ng
Lake Chad
Surrounded by Cameroon, Chad, Niger,
and Nigeria-all countries with fast growing
populations
 Shrunk 96% within 40 years
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High demand for irrigation water and declining
rainfall draining dry the rivers and streams
that feed Lake Chad
Africa’s Lake Chad
Overview
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Water demand has tripled over the last 50 years
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Climate change affects water supplies
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Drilling of millions of irrigation wells has pushed water
withdrawals beyond recharge rates
Rising temperatures = higher evaporation rates, altering
rainfall patterns, and melting glaciers
Countries pressing against the limits of water supply
satisfy the growing need of cities and industry by
diverting irrigation water from agriculture and importing
grain to offset the loss of productive capacity
Water = Food
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One Person = 4 liters of water/day
Production of food = 2,000 liters
70% water = irrigation
20% water = industry
10% water = residential purposes
Risk of Water Shortages
Water Tables Falling
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Fossil aquifers are not replenishable
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Depletion brings pumping to an end
For more arid regions, loss of irrigation water means
end of agriculture
North China’s Plain’s water table, producing over
½ of the country’s wheat and a 33% of corn, is
dropping 3 meters/yr
Wheat farmers pump from a depth of 300
meters, raising pumping costs so high that
farmers are forced to abandon irrigation
Water Tables Falling
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China
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Mining underground water
near the Hai, Yellow, and Huai
Rivers
Takes 1000 tons of water = 1
ton of wheat
40 million tons of wheat feeds
120 million Chinese compared
to 2 billion
India
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100 million farmers drilled 21
million wells, investing $12
billion in wells and pumps
Electricity blackouts occur
where ½ is used to pump
water from depths up to a km
Water Tables Falling
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In southern India,
falling water tables
dried up 95% of wells
owned by small
farmers
Irrigated land is
reduced by half over
a decade
Farmers are forced to
return to dryland
farming
Water Tables Falling
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Some use modified oil-drilling
technology to reach water,
going as deep as 1,000
meters
15% of India’s food supply
produced by mining
groundwater
Texas, Oklahoma, and
Kansas – 3 leading grainproducing states – the
underground water table
dropped by more than 30
meters
Water Tables Falling
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Colorado River
Drawn by AZ, CA,
CO, NV, NM, UT, WY
 Irrigated area decline
from 1997-2002
 CA and CO dropped
2% and 24%
respectively
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Water Tables Falling
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Iran
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71 million people
Overpumping aquifers by
an average of 5 billion
tons of water/yr – 33% of
its annual grain harvest
Water table is falling 2.8
meters/yr
Saudi Arabia
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25 million people
Water-poor as it is oil-rich
Wheat harvest dropped
from 4.1 million tons in
1992 to 2.7 million tons in
2007, 34%
Water Tables Falling
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Yemen
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22 million people
Annual water extraction of
223 million tons exceeds
annual recharge of 42
million tons, water table
dropping 6 meters/yr
Grain production falling by
2/3 over the last two
decades
Now imports 4/5 of its grain
supply
Ranks 24th of failing states
Water Tables Falling
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Mexico
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107 million people
Demand of water is
outstripping supply
Guanajuato – water table is
falling 2 meters or more a
year
Sonora farmers used to
pump water from the
Hermosillo aquifer at a depth
of 35 ft. Now more than 400
ft.
51% of the water extracted
from underground is from
aquifers being overpumped
Water Tables Falling
Overpumping of aquifers is happening in
many countries
 Depletion of aquifers and the harvest
cutbacks could be simultaneous
 Depletion of aquifers = unmanageable
food scarcity
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Rivers Running Dry
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Colorado River
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Yellow River
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Largest river in northern China
Nile River
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Major River in the southwestern US
Lifeline of Egypt
Indus River
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Supplies most of Pakistan’s irrigation water
Rivers Running Dry
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Colorado River
Rarely makes it to
the sea
 Goes through CO,
UT, AZ, NV, and CA
 Demand is
destroying the
river’s ecosystem,
including fisheries
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Rivers Running Dry
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Yellow River
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Flows 4,000 km
through 5 provinces
before it reaches the
Yellow Sea
First ran dry in 1972
and since 1985 it has
often failed to reach
the sea
Rivers Running Dry
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Nile River
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Before the Aswan
Dam was built, 32
billion cubic meters of
water reached the
Mediterranean each
year
After the dam,
increasing irrigation,
evaporation, and
demands reduced its
discharge to less
than 2 billion cubic
meters
Rivers Running Dry
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Indus River
 Originating in the
Himalayas and goes into
Indian Ocean
 Demand has made the
river run dry in its lower
reaches
 Population of 164 million,
Pakistan ranks 12th on the
2007 list of failing states
 Allocating water among
competing interests is part
of an emerging politics of
resource scarcity
Lakes Disappearing
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As river flows are
reduced lakes have
been shrinking; Lake
Chad Central Africa,
the Aral Sea Central
Asia, and the Sea of
Galilee
Most notable losses
the Aral Sea cotton
farming used up all the
water which raised salt
content and killed fish
Aral Sea Today
China, Got Water?
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1,000 lakes have
disappeared over the past
50 years
Average rate of 20 lakes
lost each year
The government had set
up 160 wetland protection
zones and invested heavily
in measure to prevent
pollution
How much is water in the Desert,
an Economy lesson
It takes 14 tons of water to make a ton of
steal which sells for $560
 It takes 1,000 tons of water to grow a ton
of wheat which sells for $200
560/14 = $40 per ton of water
200/1000 = $0.20 per ton of water
 Cities use more water than farming and
have a higher need for water
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Water Law
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Riparian vs. Appropriation “First in time, first in
right”
Colorado water law
Right to use, who has more right?
Do cities have greater need than farmers
Will water become the new oil when countries
don’t produce their own, or have a food supply
International water wars?
Solutions or “The End”
How much water is there, how much water
was there?
 Can we get more water?
 Most water distputes are local and in high
population areas, not worldwide
 Over population and standards of living,
living on less
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THE END