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Agriculture Can We Feed The World?

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NOT associated with wealth, gross national product or economic development ... Weather and Climate Profoundly Affect Crop Production ... – PowerPoint PPT presentation

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Title: Agriculture Can We Feed The World?


1
Agriculture Can We Feed The World?
  • Grant R. Cramer
  • Plant Biology 330
  • Fall 2001

2
Humanity has grown in numbers over time
7,000
6,000
5,000
4,000
Millions of people
3,000
2,000
1,000
0
0
500
1000
1500
2000
2500
Year
3
Global Population Continues to Rise
4
Different Assumptions, Different Projections
5
Fertility Declines, Real and Projected
6
Decrease in population growth rate
  • NOT associated with wealth, gross national
    product or economic development
  • IS associated with increased education,
    especially the education of mothers

7
More Children Are Attending School
8
More Adults Can Read
9
Yields Are Up, But Growth is Slowing
5
4
3
Yield (metric tons/hectare)
2
1
0
Wheat Yield
Rice Yield
Maize Yield
10
Yields Are Up, But Growth is Slowing
12
10
8
Increase in Yield
6
4
2
0
-2
Wheat
Paddy Rice
11
Trends in Per Capita Food Production
12
Intensive Agricultural has Benefited Mankind
  • 24 more food per person today than in 1961
    despite an increase of 89 more people
  • 40 lower food prices than in 1961 (in real terms)

13
Demand for Food Growing Faster than Population
  • Increase in affluence leads to greater meat
    consumption
  • Meat production growing 50 faster than crop
    production
  • Meat production much more energy intensive
  • 7 kg of grain per kg of pork 5 kg of grain per 1
    kg of beef 2 to 3 kg of grain per kg of eggs,
    cheese or poultry

14
Despite Gains, Millions Go Hungry
15
Final Analysis
  • Economic and agricultural development do not
    necessarily abolish hunger
  • Equitable distribution is also important and is
    governed by social, economic and political
    influences

16
Weather and Climate Profoundly Affect Crop
Production
  • Affects sunlight, moisture, temperature and
    natural disasters
  • By far, the lack of water is the most significant
    constraint to agricultural production in all
    agricultural zones tropical, sub-tropical and
    temperate
  • Temperature also constrains crop production in
    the temperate zones

17
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18
Humans Can Affect the Climate and Influence
Agricultural Production
  • Desertification in the Sahel
  • Greenhouse Effect

19
Global warming enhanced by emissions of man-made
gases
Source Climate Change, State of Knowledge,
OSTP, 1997
20
Greenhouse gas warming
21
Much is known with certainty about global warming
  • Existence of natural greenhouse effect is
    established beyond doubt
  • Concentrations of greenhouse gases (GHGs) are
    increasing
  • The temperature of the earth is increasing. 1998
    the hottest in at least 1000 years.
  • Sea levels are rising (4 to 10 inches over past
    100 years)
  • Some GHGs will remain in the atmosphere for
    centuries

22
CO2 is building up in the atmosphere
Source Climate Change, State of Knowledge,
OSTP, 1997
23
Atmospheric methane (CH4) concentrations
Data Source D.M. Etheridge et al. Concentrations
of CH4 from the Law Dome (East Side, "DE08" Site)
Ice Core(a), Commonwealth Scientific and
Industrial Research Organisation, Aspendale,
Victoria, Australia. September 1994. Available
http//cdiac.esd.ornl.gov/ftp/trends/methane/lawdo
me.259. M.A.K. Khalil, R.A. Rasmussen, and F.
Moraes. "Atmospheric methane at Cape Meares
Analysis of a high resolution data base and its
environmental implications." Journal of
Geophysical Research 9814,753-14,770. 1993.
Available http//cdiac.esd.ornl.gov/ftp/db1007/cm
eares.mon
24
Earths temperature continues to rise rapidly
Source Climate Change, State of Knowledge,
OSTP, 1997
25
Earth is projected to grow warmer
Source Univ. of East Anglia, IPCC
26
The polar ice cap is melting
27
Uncertainties still persist
  • Timing and regional impacts
  • The effects of increased cloudiness
  • Uncertain health and ecological impacts
  • Possible surprises from unanticipated effects

28
More impacts of global warming can be expected
  • More health effects from the spread of tropical
    diseases, heat waves, and so-called natural
    disasters
  • Loss of agricultural land in developing countries
  • Disappearance of ecosystems that are unable to
    migrate

29
Cumulative carbon emissions, 1950-1996
Data Source Marland et al, 1999. Carbon Dioxide
Information Analysis Center.
30
Per capita emissions of carbon from industrial
sources, 1996
Data Source Marland et al, 1999. Carbon Dioxide
Information Analysis Center.
31
Vehicle numbers are rising dramatically
32
Motor vehicle use is highest in developed
countries
33
Success story CFC production has fallen sharply
34
How Much Arable Land is There
  • Only 12 of the world soils are arable
  • 26 is for pastures
  • 31 for forests

35
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36
World Agricultural Land Distribution
  • Latin America, Sub-Saharan Africa and the former
    Soviet Union have the most agricultural land
  • Europe (71), South Asia (73) and Southeast Asia
    (47) have highest percentage of total land as
    agricultural land
  • 70 of South Asia and Southeast Asia agricultural
    land is the most intensive

37
Increased resource use for increased crop
production
  • Introduction of new crops
  • Mechanization
  • New and improved varieties
  • Inorganic fertilizers
  • Irrigation
  • Pesticides

38
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39
More fertilizer More food
40
Food Supply Increasingly Relies on Irrigation
41
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42
Irrigated Soils Today
  • 15 of the arable soils
  • Twice as productive as rain-fed soils
  • Produce a third of the worlds food
  • Subject to salinization in semi-arid environments

43
Are These Practices Sustainable?
  • What are the impacts of
  • Land Degradation
  • Energy
  • Pesticides
  • Genetically Uniform Crops

44
Land Degradation
  • 15 of total world soils (1964 Mha of 13,077 Mha)
    lost to soil degradation in the last 45 years
  • 38 of cropland 21 of pasture 18 of forests
    resulting in 13 loss in productivity for
    croplands
  • Most of this lost is due to wind and water
    erosion (1725 Mha)
  • Nutrient loss (135 Mha)
  • Salinity (77 Mha)

45
Human-Induced Degradation
  • 35 attributed to overgrazing
  • 28 attributed to agricultural-related management
  • 29 attributed to deforestation

46
Degraded Soil Means Less Food
World Totals (million hectares) Vegetation
Removal 579 Overexploitation 133 Overgrazing 679
Agricultural Activities 522 Industrial and
Bioindustrial 23
47
Forest Loss Is Severe in the Tropics
48
Many of Earths Forests Have Been Cleared or
Degraded
49
Amazon Deforestation Remains High
50
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51
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52
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53
Energy
  • In past, 5 to 10 of the final value of the crop
  • Today, 50 of the final value of the crop
  • Modern US agriculture puts in 80 times as much
    energy per kilogram of rice as traditional Asian
    practices with only a 4.5 fold increase in
    production
  • Even so, this is still only 3 to 5 of energy
    used to get your food on the shelf

54
Pesticides
  • Used extensively today
  • Estimated crop losses to pests are 30 today with
    pesticides and could be twice as much without
    pesticides
  • Can cause serious environmental pollution
  • Pests are building up resistance
  • Problems approached through IPM and Plant
    Biotechnology

55
Genetically Uniform Crops
  • Advantages uniform quality and harvest date
  • Disadvantages loss of important germplasm
    narrower ecosystem more susceptible to
    catastrophic damages from environmental stress,
    disease and pests

56
How Much Are Natures Services Worth?
Global GNP (US 18 trillion)
Ecosystem Services (US 33 trillion)
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