At 02:07 PM 12/1/97 -0600, Neil Rest wrote:
>Harry Pollard <[EMAIL PROTECTED]> wrote:
>
>>If we run out of something, we'll use something else. We are
>>a small species spread thinly across an enormous planet.
>
>Mr. Pollard, what planet is it that you are talking about? Out species
>consumes an immense fraction of the total biomass of Earth. (I could look
INVESTING IN NATURAL CAPITAL:
THE ECOLOGICAL APPROACH TO SUSTAINABILITY
from the International Society for Ecological Economics
http://kabir.umd.edu/ISEE/ISEEhome.html
HOW CLOSE TO PRACTICAL LIMITS?
"There is accumulating evidence that humanity my soon have to
confront the real carrying capacity constraints. For
example, nearly 40% of terrestrial net primary productivity
(photosynthesis) is already being used ("appropriated") by
humans, one species among millions, and this fraction is
steadily increasing (Vitousek et al. 1986). If we take
this percentage as an index of the human carrying capacity
of the earth and assume that a growing economy could come
to appropriate 80% of photosynthetic production before
destroying the functional integrity of the ecosphere, the
earth will effectively go from half to completely full
within the next doubling period -- currently about 35 years
(Daly 1991).
"The significance of this unprecedented convergence of
economic scale with that of the ecosphere is not generally
appreciated in the current debate on sustainable
development. Because the human impact on critical functions
of the ecosphere is not uniform "effective fullness" may
actually occur may actually occur well before the next
doubling of human activity. (Liebig's law reminds us that
is takes only a single critical limiting factor to constrain
the entire system.) Indeed, data presented in this chapter
suggests that long-term human carrying capacity may already
have been at less than the present 40% preemption of
photosynthesis. If so, even current consumption (throughput)
cannot be sustained indefinitely, and further material
growth can be purchased only with accelerated depletion of
remaining natural capital stocks.
"This conundrum can be illustrated another way by extrapolation
from our ecological footprint data. If the entire world
population of 5.6 billion were to use productive land at
the rate of our Vancouver/Lower Fraser Valley example, the
total requirement would be 28.5 billion ha. In fact, the
total land area of Earth is only just over 13 billion ha, of
which only 8.8 billion ha is productive cropland, pasture,
or forest. The immediate implications are two-fold: first,
as already stressed, the citizens of wealthy industrial
countries unconsciously appropriate far more than their
share of global carrying capacity; second, we would
require an additional "two Earths," assuming present
technology and efficiency levels, to provide for the present
world population at Canadian's ecological standard of
living. In short, there may simply not be enough natural
capital around to satisfy current development assumptions.
The difference between the anticipated ecological footprint
of the human enterprise and the available land/natural
capital base is a measure "sustainability gap" confronting
humankind." [p. 383]
A CAUTIONARY NOTE
"We admittedly make no allowance for potentially large
efficiency gains or technological advances. Even at
carrying capacity, further economic growth is possible (but
not necessarily desirable) if resource consumption and
waste production continue to decline per unit GDP (Jacobs
1991). We should not, however, rely exclusively on this
conventional rationale. New technologies require decades to
achieve the market penetration needed to significantly
influence negative ecological trends. Moreover,there is no
assurance that savings will not simply be directed into
alternative forms of consumption. Efficiency improvements
may actually increase rather than decrease resource
consumption (Saunders 1992). We are already at the limit in
a world of rising material expectations in which the human
population is increasing by 94 million people per year. The
minimal food-land requirements alone each year for this
number of new people is 18,800,000 ha (at 5 people/ha, the
current average productivity of world agriculture) -- the
equivalent of all cropland in France." [p. 386]
- - - - - - - - - - - - - - - - - - - - - -
From: INVESTING IN NATURAL CAPITAL, ISBN 1-55963-316-6
PUBLISHED BY:
The International Society for Ecological Economics
http://kabir.umd.edu/ISEE/ISEEhome.html and
Island Press -- 1994 http://www.islandpress.com
1-800-828-1302 or 1-707-983-6432 Fax 1-707-983-6164
EDITED BY:
AnnMari Jansson, Monica Hammer,
Carl Folke, and Robert Costanza
The quoted text was taken from chapter # 20 which was by:
William E. Rees and Mathis Wackernagel
The University of British Columbia
School of Community and Regional Planning
6333 Memorial Road
Vancouver, BC Canada V6T 1Z2
REFERENCES:
Daly, H. 1986. Comments on "Population Growth and Economic
Development." Population and Development
Review 12: 583-585
------- 1990. Sustainable development: from concept and
theory towards operational principles.
Population and Development Review (special
issue 1990) (Also published in Daly, H. 1991.
Steady State Economics. 2d, ed. Washington,
DC: Island Press)
--------1991. From empty world economics to full world
economics: recognizing an historic turning
point in economic development. In
Environmentally Sustainable Development:
Building on Brundtland, eds. R. Goodland, H.
Daly, and S. El Serafy. Washington DC: The
World Bank
--------1991. Steady State Economics. 2d, ed. Washington,
DC: Island Press
Vitousek, P., P. Ehrlich, A. Ehrlich, and P. Matson, 1986.
Human appropriation of the products of
photosynthesis. BioScience 36: 368-74
