• Projected increase to 8 billion by the year 2050

Figure 1. Population projections and exponential growth

• Now use or have destroyed 40% of planetary organic output
• Conflicting opinions - experts, religious, business, enviros

Terminology

Carrying capacity- the # of persons that economy or environment can support at an acceptable standard of living. Importance of carrying capacity - rational basis for defining limits to a country's population.

Per capita - resource per person per year

Fig. 2. Resource curves and per capita calculations

Sustainable yield - amount of product that can be produced indefinitely.

Natural capital - resource that is exhausted if harvested beyond its sustainable yield . Many countries , especially poorThird World countries, are now eating into their "principal" or natural capital to sustain population growth. Wiser course is to allow only population that can survive on sustainable yield....

What resources limit carrying capacity?

• Food - Water - Land area - soil fertility - climate
• Energy and mineral resources
• Ingenuity and productivity can also overcome lack of natural resources,i.e. Japan!

Earth and its carrying capacity

• Imports only sunshine
• Finite resource base
• Many sustainable resource if not over-used
• Inability to import resources, desire to retain some of natural world, and efficiency in using existing resources determines carrying capacity of planet

Population Statistics

• 5.8 billion and 1.8% population growth
• UN estimates 1.3 billion in poverty, < $1/day income
• 90 million new people each year - equals population of Mexico
• 20% of world's poorest get 1.4% of global income
• 20% of richest get 70% of world income

Food - Revolution and Evolution

• Agricultural revolution - food outstrips population through 1985
• Post-1985 - ag evolution - food growth slows to level less than pop increase


Fig. 3. Actual population and food growth and per capita since 1960


• Factors contributing to decrease in growth of food production- loss of crop land , limits of present crop strains, climatic, population increase, less irrigation, humans move up food chain (SE ASIA).

Food facts

• US exports 50% of global imports -100 nations
• 1996 - bad US corn crop - grain prices doubled
• Food national security - political issue
• World grain stocks at all-time low in 1996. Demand has exceeded supply for past several years.
• 1.2 billion people spend 70% of income on food. Higher food prices - disastrous.
• In US, food is and will remain cheap.

The challenge

• Develop more productive grain strains
• Family planning - need 0% pop. growth
• Stem loss of farmland
• Develop consensus for sustainable economy

How Much Growth is Enough? A sampling of views....

• Business - Dane Cty Ch Commerce proclaims (1994) "if business in Dane Cty doesn't grow, county will die". Equates lack of growth with death. Comment: Indefinite growth is unsustainable and harms envir and QOLife.
• Religious - Dane Cty Right to Life publicly proclaims (1995) "the earth can support 53 billion people". Draw your own conclusions. What about other species?
• Science - 1600 scientists including 102 Nobel laureates issue 1994 document "Warning to humanity" - states "no more than one or several decades remain before the chance to avert the threats we now confront will be lost and the prospects for humanity immeasurably diminished. A new ethic is required - a new attitude towards discharging our responsibilities for caring for ourselves and the earth. This ethic must motivate a great movement ... to effect great changes...."

Experts Disagree on "inevitability" of a food crisis

• Worldwatch Organization
• Generates lots of research and press releases suggesting imminent food crisis. Excellent resource. Worldwatch projections are disputed by other organizations, but are widely viewed as useful portents.
• International Food Policy Resaerch Institute
• Believe that as grain prices increase due to increasing demands, countries and markets will respond by increasing production, curtailing livestock's use of grain (40% of global usage), and investing in agricultural research that will improve yields. This is a realistic and feasible scenario.
• Food and Agricultural Organization UN (FAO)
• An incredible statistical resource for the production of most agricultural products. FAO projections suggest that a food crisis is not imminent, but will be concentrated in certain vulnerable regions such as the sub-Saharan Africa.

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