Our Water Resources

Resources and ManThe Malthusian trapThe kinds of resources– renewable resources– Nonrenewable resources– Potential ly renewable resources

The nature of exhaustibility

SELF-ACTUALI-ZATION

SOCIAL

SECURITY

PHYSIOLOGICAL

ESTEEM

Food is the most basic of allour needs

MASLOW’S HIERARCHY OF NEEDS

Thomas Malthus

increases in geometric increases in geometric progression, the progression, the resources to sustain this resources to sustain this growth do not. Thus, if growth do not. Thus, if population grows too population grows too much faster than food much faster than food production, this growth production, this growth is checked by famine, is checked by famine, disease, and war.disease, and war.

Thomas Malthus (1766-1834)Thomas Malthus (1766-1834)InIn “An Essay on the Principles of “An Essay on the Principles of Population”Population”, , published in 1798,published in 1798, Thomas Thomas Malthus argued that while populationMalthus argued that while population

This should ordinarily signal disaster. Take the case of wolves and moose at Isle Royale National Park, Lake Superior, for instance.

3000

4000

5000

1000

2000

1900 1920 198019601940 2000

50

3040

20100

The sustainable levels forIsle Royale inhabitants

Wo

l f po

pu

latio

nM

oo

se p

op

ula

tio

n

18000

15

30

45

1850 1900 1950 2000Source: A. Maddison, Monitoring the World Economy 1820-1992 (OECD, Paris, 1995).

Economy

Population

Re

lati

ve t

o t

he

1820

leve

l

World’s population, a little over a billion at the time of Malthus, has multiplied about six-fold since then.

Measured in inflation-adjusted dollars, world’s total output, now about $40 trillion, was about $700 billion at the time of Malthus.

Clearly, economic growth has been more strongly exponential than that of the demand (population growth) that created it.

0

2

4

6

1950 1960 1970 1980 1990 2000

Valu

es r

ela

tiv

e t

o 1

95

0

Gross World Product

World Grain Production

World Population

0

2

4

61 2 3

World Grain OutputG

ros

s W

orl

d P

rod

uc

t

0

1

2

3

Wo

rld P

op

ulatio

n

The growth in world’s grain output has been faster than

population but world economy has growth even faster.

Adam Smith (1723-1790),Adam Smith (1723-1790),

Wealth of NationsWealth of Nations (1776), (1776), that every individual in that every individual in pursuing his or her own pursuing his or her own good is led, as if by an good is led, as if by an invisible hand, to invisible hand, to achieve the best good achieve the best good for all. Therefore any for all. Therefore any interference with free interference with free competition by the competition by the government is almost government is almost certain to be injurious.certain to be injurious.

the British philosopher and economist, the British philosopher and economist, argued, in his celebrated treatise argued, in his celebrated treatise An An Inquiry into the Nature and Causes of theInquiry into the Nature and Causes of the

First Green Revolution in this century took place in developed countries

during 1950-70.

First Green Revolution

Second Green Revolution has occurred in developing countries

since mid-1960s.

Second Green RevolutionFirst Green Revolution

0.5

1.0

1.5

2.0

1940 1960 1980 2000

100

200

300

400 Pe

r Ca

pita

Gra

in A

va

ilab

ility (k

g p

er y

ea

r) W

orld

Gra

in P

rodu

ctio

n (b

illio

n to

ns p

er y

ear)

Despite the tremendous strides in world grain pro-duction, per capita grain availability has remained unchanged since the mid-1970s*.

*Lester R. Brown: “Facing the Prospect of Food Scarcity” in STATE OF THE WORLD 1997 (Worldwatch Institute, 1997)

Currently,the annual food production

world-wide, including grains,

poultry, seafood and meat,

is about 4 bil l ion tons per year, orabout 4½ lbs per person per day.

from ~1500 lbs per year in America, to

But per capita food consumption varies, worldwide,

~1000 lbs per yearin Mediterranean/Middle East region, and

about 500 lbs per year in India and South Asia.

Being largelystenohumid as well asstenothermal,agriculturalcrops imposea rather restrictedrange of climatic conditions. Farmland therefore tends to be in short supply.

Mea

n A

nnua

l Tem

pera

ture

(C

) o

0

15

30

Mean annual precipitation (cm)

0 400

Tropical Forest

Des

ert G

rass

land

Arctic and alpinetreeless areas

100 200 300

Farmland

Coniferous Forest(green year-round)

Deciduous Forest(seasonal loss of leaves)

Oceans (71%)

Land(29%)

Most of theEarthiscoveredby water

“...water, water, every wherenor any drop to drink!”

In use

Potentialfarming

Unusable

Potentialgrazing

Cultivated11%

Grazed10%

14%Forests, semi-arid6% Arid

Ice, snow, deserts,mountains (51%)

8%Tropicalforests

Oceans (71%)

Land(29%)

andbarely a fifth of itis available forfarming related activities.

But the supply of land too is limited...

Economic growth exacerbates the demand for water, e.g.,

• with economic growth at 7-10% per year, poultry consumption is rising at the rate of 15% per year in India, Indonesia and China − the water demands of this nontraditional industry are only likely to grow;

• we need about 250,000 gallons of water to produce a ton of corn, 375,000 gallons to produce a ton of wheat, 1,000,000 gallons to produce a ton of rice, and 7,500,000 of water to produce a ton of beef.

Farming (41%)Public(10%)

Industry(11%)Power-

Plant (38%)Farming (85%)

Public (6%)

Industry(7%)

Power-Plant (2%)

U.S.A. China

•to which we should also add industry’s needs.

Source: Worldwatch Institute

this comparison of U.S. and China shows how economic growth necessitates increased use of

water for nonagricultural purposes.

How much How much water do water do we have?we have?

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/smry.rxml

The hydrological cycleIgnoring such long-term effects as the changes in atmospheric storage conditions, run-off filling the ocean basins etc., hydro-logicalcycle ismerelythe re-cycling of waterbetweenland andoceans.

How much water in the hydrosphere?Conventional estimate assumesa total groundwater storage of about 1,700 quadrillion gallons. This gives the estimate of hydrosphere’s total water content as 3.5x1020 gallons.

Oceans (97%)

Ice (1.2%)

Underground water (0.5%)Surface water (0.02%)

Atmosphericmoisture (0.001%)

An alternate assumption is that pores in sediments contain about 80,000 quadrillion gallons of groundwater (almost 50 times the conventional estimate). This yields an estimate of about 4x1020 gallons of water in the entire hydroshere.

Oceans (80%)

Ground-water (19%)

Groundwater (19%)

Ice (1%)Surface water (0.002%)

Atmosphere(0.001%)

Farming (41%)Public(10%)

Industry(11%)Power-

Plant (38%)Farming (85%)

Public (6%)

Industry(7%)

Power-Plant (2%)

U.S.A. China

As is evident from the comparison of water use in the U.S. and China, economic growth necessitates increasing use of water for power generation.

Source: Worldwatch Institute

0.6

0.3

- 0.3

0.0

- 0.61900 1950 2000

Global mean temperature change through the past century

Source: NOAA and NASA

5-yearrunningaverage

Tem

pe

ratu

re C

ha

ng

e (

ºC)

Se

a l

ev

el

rela

tiv

e t

o 1

95

1-7

0 (

cm

)

8

0

4

-12

-8

-4

1900 20001950

5-yearrunningaverage

The global mean sea-level rise through last century

Source: T.P. Barnett, in CLIMATE CHANGE (IPCC Working Group Report: Cambridge University Press, 1990)

Steric height (dynamic cm

)

Distance off California coast (km)500 400 300 200 100 0

100

95

90

85

80

1985-91

1950-56

0

100

200

300

400

500

0 0.3 0.6 0.9 1.2∆T (oC)

Dep

th (m

)The 1950-91 hydrographic data off California coast show that

sea surface waters (0-100m) became~0.8oC warmer in the 35-year period between 1950-56 and 1985-91; which

raised the sea level sur-face by 3.1+0.7 cm.

Note: Warming by 1oC the top 100 m of ocean with 15oC temperature and 3.4% salinity should raise the sea level by ~2.2 cm.

Source: D. Roemmich, SCIENCE: v. 257, p.373-375 (July 17, 1992).

80

85

90

95

100

0100200300400500

Distance off California coast (km)

Ster

ic he

ight (

dyna

mic c

m)

Dean Roemmich: Ocean warming and sea level rise along the southwest U.S. coast [Science: 257 ( 373-375), 1992]

1985-1991

1950-1956

Sea surface off California has risen by about 2 cm, on average, between 1950 and 1991

OceansPore water in the

sedimentsIce-caps, glaciers

Rivers, lakesAtmospheric

moisture

Total hydrosphere

Total mass(trillion tons)

1,370,000

330,00020,000

300

13

1,720,313

Share of thehydrosphere

80%

18.8%1.2%0.02%

0.0008%

100%

Considering all sediments*

Total mass(trillion tons)

1,370,000

7,00020,000

300

13

1,397,313

Share of thehydrosphere

97%

0.5%1.4%0.02%

0.0009%

100%

Conventional estimates

The availability of water too is a limiting factor. An average human needs about 300,000 gallons of water annually, including 250,000 gallons for growing food. Indeed, nations with under 150,000 gallons of annual per capita water supply face severe limits to their growth.

Mass of the present hydrosphere

*Karl K. Turekian: GLOBAL ENVIRONMENTAL CHANGE (Prentice Hall, 1996)

Seafood is an important source of animal protein worldwide,

nonetheless.

World fish harvest: Note that Indian Ocean has the least yield.

Area(106 km2)

Volume(106 km3)

Pacific OceanAtlantic Ocean

Indian Ocean

707.6323.6291.0

165.282.473.4

An

nu

al f

ish

ha

rve

st (

mill

ion

to

ns

)

Ocean area (km2)Pr

imar

y pr

oduc

-tio

n (g

C/m

2 /yr)

Average number of

trophic steps

Net transfer efficiency

Total fish production

(tons/yr)

OceanicCoastalUpwelling

325x106 (90%)36x106 (9.9%)36x104 (0.1%)

50100300

53

15

0.00010.0331.1

1.63x106 (<1%)120 x106 (~50%)120x106 (~50%)

World fish production*

* J.H. Ryther: Science, 166 (1969): 72-76

Even the maximum

possible yield from

world’s oceans

can hardly suffice.

Annual fish harvests of the leading

nations.

Seafood is already a major source of animal protein in the Asian diet.

That Climate Thing

•Global warming and its consequences

•The anthropogenic contributions

Number of Fatalities per Event

3 30 300 3,000

3

0.3

0.03

Tornadoes

FloodsTornadoesHurricanesEarthquakes

Cu

mm

ula

tive

Nu

mb

er

of

Eve

nts

pe

r Y

ea

r

0.1

1

10

0.011 10 100 1,000 10,000

Floods

Hurricanes

Earthquakes

U.S. 20th Century Natural Disaster Fatality-Frequency Plots*

* S.P. Nishenko and C.C. Barton: “Scaling Laws for Natural Disaster Fatalities” in REDUCTION AND PREDICTABILITY OF NATURAL DISASTERS (Eds: Rundle, Turcotte and Klein) (Addison-Wesley, 1996)

* International Federation of Red Cross and Red Crescent Societies (The Economist, Sept 6, 1997)

High wind: 21%

Earthquake: 8%

Flood: 19%

Other naturaldisasters: 21%

Volcanoes: 1%

Drought & Famine: 6%Landslides: 3%

Man-madedisasters: 34%

Disasters*by type: 1971-96

Total: 8,219,000

Tem

pera

ture

Ch

an

ge (

C)

o

0.6

0.3

- 0.3

0.0

- 0.61900 1950 2000

Global mean temperature change through last century

Source: Thomas Karl and C. Bruce Baker: GLOBAL WARMING UPDATE (NCDC-NOAA, 1994)

5-year runningaverage

1950-60 Mean level

Se

a l

ev

el

rela

tiv

e t

o 1

95

1-7

0 (

cm

)

8

0

4

-12

-8

-4

1900 20001950

5-year runningaverage

The global mean sea-level rise through last century

Source: T.P. Barnett, in CLIMATE CHANGE (IPCC Working Group Report: Cambridge University Press, 1990)

Mean 1951-1970 level

T (

C)

-0.8

-0.4

0

0.4

0.8

800 1000 1200 1400 1600 1800

∆o

2000

Little Ice Age

Winter conditions in Eastern Europe through the past millenium, based on manuscript records*

* J. Imbrie & K.P. Imbrie: ICE AGES (Enslow Publishers, 1979)

Steric height (dynamic cm

)

Distance off California coast (km)500 400 300 200 100 0

100

95

90

85

80

1985-91

1950-56

0

100

200

300

400

500

0 0.3 0.6 0.9 1.2∆T (oC)

Dep

th (m

)The 1950-91 hydrographic data off California coast show that

the sea surface waters (0-100m) became ~0.8oC warmer in the 35-year period between 1950-56 and 1985-91; which

raised the sea level sur-face by 3.1+0.7 cm.

Note: Warming by 1oC the top 100 m of ocean with 15oC temperature and 3.4% salinity should raise the sea level by ~2.2 cm.

Source: D. Roemmich, SCIENCE: v. 257, p.373-375 (July 17, 1992).

20%

0%

- 60%

- 20%

- 40%

Global warming will hurt the poor nations most!

Change in average national crop yield by the year 2,060 compared to yield corresponding to no change in climate

(based on the ocean-atmosphere coupling model) - SCIENCE NEWS, Aug 1992

Ocean Storage1,370,000,000 km3

The Hydrological Cycle

Precipitation285,000 km3

Evaporation320,000 km3

Precipitation95,000 km3

Evaporation60,000 km3

Run-off35,000 km3

Flo

w o

f C

olor

ado

Riv

er b

elow

all

maj

or d

ams

and

d

iver

sio

ns

(bil

lio

n m

/yr)

3

40

30

10

20

20001900 1920 1940 19801960Sandra Postel: Forging a Sustainable Water Strategy (STATE OF THE WORLD 1996: Worldwatch Institute , 1996)

Colorado River

Mexico

United States

Str

ea

m F

low

in

to A

ral S

ea

(b

illio

n m

/ye

ar)

3Drying of the Aral Sea

Sandra Postel: Forging a Sustainable Water Strategy (STATE OF THE WORLD 1996: Worldwatch Institute , 1996)

1940 2000198019600

80

20

40

60

Aral Sea

Removable volume(in 1012 m3)

4.03.0

10.0

600.00.1

500.01.12.2

56.0220.0

3.38.6

-1.9

1406.7

North America

High plainsSouthwestCalifornia

Africa and Asia

SaharaSahel (soil water)ArabiaAral (Sea: 1960)Aral (groundwater)Caspian (Sea)Caspian (groundwater)

Worldwide

DeforestationWetland reductionDams

Total

Extraction rate(in 1010 m3/yr)

1.201.001.30

1.000.341.602.703.700.770.47

4.900.20

-

19.20

Sea-level riserate (mm/yr)

0.030.030.04

0.030.010.040.080.100.020.01

0.140.01

-

0.54

Estimated sea-levelchange to date (mm)

1.10 0.92 1.20

0.56 0.28 0.89 2.20 3.10 1.30 0.78

3.40 1.30-5.20

11.80

A century of human induced sea level rise*

* Walter Newman and Rhodes Fairbridge: The Management of Sea-level Rise (NATURE, v. 320, p. 319-328, 1986). Dork Sahagian, Frank Schwartz and David Jacobs: Direct Anthropogenic Contributions to Sea-level Rise in the Twentieth Century (NATURE: v. 367, p. 54-57, 1994).

20%

0%

-20%

Change inprecipitation (1900-94)

Thomas Karl, Neville Nicholls & Jonathan Gregory:THE COMING CLIMATE, Scientific American, May 1997

The 1900-94 trends reveal a general tendency towards greater

precipitation (a) at higher latitudes and (b) on

land

La

titu

de

40oS

0o

40oN

0

- 10 20100

Precipitation Change (%, 1900-94)

- 1 21

Land, as % of Global Surface Area

Comparing the 1900-94 precipitation change with (a) latitude and (b) land area

Ocean Storage1,370,000,000 km3

The Hydrological Cycle

Evaporation320,000 km3

Precipitation285,000 km3

Evaporation60,000 km3

Precipitation95,000 km3

Run-off

35,000 km3

In summaryIn summary,,• Human ingenuity has defied the Human ingenuity has defied the

“Malthusian Trap”, that “Malthusian Trap”, that the power of the power of population exceeds that of the earth.population exceeds that of the earth.

• This has resulted in modifying the most This has resulted in modifying the most basic of nature’s processes - the basic of nature’s processes - the hydrological cycle.hydrological cycle.

• Perhaps technology defies the Gandhian Perhaps technology defies the Gandhian dictum, that “nature has enough for our dictum, that “nature has enough for our need, but not for our greed”.need, but not for our greed”.