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Agriculture Can We Feed The World? Grant R. Cramer Plant Biology 330 Fall 2001 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 Global Population Continues to Rise

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agriculture can we feed the world

AgricultureCan We Feed The World?

Grant R. Cramer

Plant Biology 330

Fall 2001

humanity has grown in numbers over time
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

decrease in population growth rate
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
yields are up but growth is slowing

1960

1965

1970

1975

1980

1985

1990

1995

2000

Yields Are Up, But Growth is Slowing

5

4

3

Yield (metric tons/hectare)

2

1

0

Wheat Yield

Maize Yield

Rice Yield

yields are up but growth is slowing10

1960

1965

1970

1975

1980

1985

1990

1995

2000

Maize

Yields Are Up, But Growth is Slowing

12

10

8

% Increase in Yield

6

4

2

0

-2

Wheat

Paddy Rice

intensive agricultural has benefited mankind
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)
demand for food growing faster than population
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
final analysis
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
weather and climate profoundly affect crop production
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
humans can affect the climate and influence agricultural production
Humans Can Affect the Climate and Influence Agricultural Production
  • Desertification in the Sahel
  • Greenhouse Effect
global warming enhanced by emissions of man made gases
Global warming enhanced by emissions of man-made gases

Source: “Climate Change, State of Knowledge,” OSTP, 1997

much is known with certainty about global warming
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
co 2 is building up in the atmosphere
CO2 is building up in the atmosphere

Source: “Climate Change, State of Knowledge,” OSTP, 1997

atmospheric methane ch4 concentrations
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/lawdome.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 98:14,753-14,770. 1993. Available: http://cdiac.esd.ornl.gov/ftp/db1007/cmeares.mon

earth s temperature continues to rise rapidly
Earth’s temperature continues to rise rapidly

Source: “Climate Change, State of Knowledge,” OSTP, 1997

earth is projected to grow warmer
Earth is projected to grow warmer

Source: Univ. of East Anglia, IPCC

uncertainties still persist
Uncertainties still persist
  • Timing and regional impacts
  • The effects of increased cloudiness
  • Uncertain health and ecological impacts
  • Possible surprises from unanticipated effects
more impacts of global warming can be expected
More impacts of global warmingcan 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
cumulative carbon emissions 1950 1996
Cumulative carbon emissions, 1950-1996

Data Source: Marland et al, 1999. Carbon Dioxide Information Analysis Center.

per capita emissions of carbon from industrial sources 1996
Per capita emissions of carbon from industrial sources, 1996

Data Source: Marland et al, 1999. Carbon Dioxide Information Analysis Center.

how much arable land is there
How Much Arable Land is There
  • Only 12% of the world soils are arable
  • 26% is for pastures
  • 31% for forests
world agricultural land distribution
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
increased resource use for increased crop production
Increased resource use for increased crop production
  • Introduction of new crops
  • Mechanization
  • New and improved varieties
  • Inorganic fertilizers
  • Irrigation
  • Pesticides
irrigated soils today
Irrigated Soils Today
  • 15% of the arable soils
  • Twice as productive as rain-fed soils
  • Produce a third of the world’s food
  • Subject to salinization in semi-arid environments
are these practices sustainable
Are These Practices Sustainable?

What are the impacts of

  • Land Degradation
  • Energy
  • Pesticides
  • Genetically Uniform Crops
land degradation
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)
human induced degradation
Human-Induced Degradation
  • 35% attributed to overgrazing
  • 28% attributed to agricultural-related management
  • 29% attributed to deforestation
degraded soil means less food
Degraded Soil Means Less Food

World Totals

(million hectares)

Vegetation Removal 579

Overexploitation 133

Overgrazing 679

Agricultural Activities 522

Industrial and

Bioindustrial 23

energy
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
pesticides
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
genetically uniform crops
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
how much are nature s services worth
How Much Are Nature’s Services Worth?

Global GNP

(US $18 trillion)

Ecosystem Services

(US $33 trillion)

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