Are environmental problems linked to population trends

1
Are environmental problems linked to population
trends?

• Nell Leshner

2

• Human survival depends on the Earth and its
  natural resources

Carrying firewood in Botswana
Human activity tends to transform the Earth
Cropland bordering rainforest, Brazil
3
Since there is a link between environmental
problems and humanity, how are environmental
problems linked to population trends?
Man cutting baobab bark for rope, Madagascar
Geese hunters and decoys, California
4
Agriculture, population growth and the environment

• Agricultural revolution ? improve production of
  calories ? increased carrying capacity

• Human activity that has most transformed the land

Farmland next to rainforest, Brazil

• Population growth ? ? food needs ? ? pressure
  on land and environment
• Extensification vs. intensification
• Obstacles to increasing food production

5
Industry, population growth, and the environment

• Industrial revolution --gt ? human productivity, ?
  carrying capacity

• I PAT
• complex interactions between I P A T

Lumber mill, British Columbia
6
The sustainability debate the intersection
between overpopulation, resource degradation
resource depletion

• - the overpopulation school sees population
  growth as the driving force behind environmental
  degradation and resource overuse
• concerns about population growth have decreased

Loggers at a clearcut, Madagascar
7
Reworking of a Malthusian model

G(t) growth of environmental stock, S r
intrinsic growth rate K environmental carrying
capacity H(t) harvesting function
G(t) r S (1 S/K) H(t) aSP dS/dt G(t)
H(t) rS(1 S/K) aSP dP/dt nP B(S,P),
where B(S,P) bSP

• Similar to a predator-prey model
• Humans are the predator and the environment in
  the prey
• An inverse relationship b/t environmental
  capital and population growth

Stranded albatross and garbage, Hawaii
8
Is the world on a trajectory of sustainable
development or is the natural environment being
overtaxed to the point that a downtown in living
standards is likely? (Brander, 2007).
Soil erosion, Hawaii
9
Are population dynamics of primary importance in
achieving sustainability? Is the Modern
sustainability problem fundamentally based on
population issues identified by Malthus?

• Environmental problems are inherently complex
• ex. externalities common-property issues
• Population trends are important
• There are other factors involved as well
• Social political institutions
• Prices

10
Conclusion

• A link exists between population trends and
  environmental problems
• Agriculture
• Industry
• The sustainability debate
• But there are other important factors at work
• More research needs to be done

11
Sources

• Brander, James A. (2007), "Viewpoint
  Sustainability Malthus Revisited?", Canadian
  Journal of Economics,Vol 40, No. 1, February
  2007, pp. 1-38.
• Pebley, Anne R. (1998), "Demography and the
  Environment", Demography v35, n4 (November 1998)
  377-389.
• Preston, Samuel H. (1996) "The Effect of
  Population Growth on Environmental Quality", in
  Population Research and Policy Review, Vol. 15,
  April 1996, pp. 95-108.
• Photos Frans Lanting