APPENDIX 24
Further Supplementary Memorandum from
The Royal Society for the Protection of Birds (RSPB)
1. You stress the need to work safely
within ecological limits as the bottom line. In the case of greenhouse
gas emissions and global warming, the concept of an environmental
limit has become widely understood and accepted. How well developed
is this concept in other areas?[62]
We know that human life depends on healthy ecosystems
that supply life-sustaining resources and absorb wastes. However,
current growth and consumption patterns are placing increasing
stress on ecosystems. This is evidenced through signs such as
environmental degradation, biodiversity loss, deforestation, and
the breakdown of social and economic systems. Each of these can
be monitored and measures in different ways, such as threatened
species status, loss of old growth forest cover etc.
Ecosystems threatened, for example, by over-harvesting
and/or overwhelmed by more wastes than can be absorbed, lose resilience
(ie the ability to absorb shocks and disturbances) and may suddenly
break down and/or settle into a different system with less resilience.
This implies there are thresholds at which the levels of stress
will lead to the disruption of the system.
One concept used to understand these critical
limits and thresholds is "carrying capacity" which assumes
that there are a finite number of people who can be supported
without degrading the natural environment and social, economic
and cultural systems and, as such, "is an indirect measure
of the maximum level of stress that the ecosystem can maintain"
(Barbier, Burgess and Folke 1994). Rees (1996) has developed this
to address per capita consumption by defining carrying
capacity not as a maximum population but rather as the maximum
"load" that can safely be imposed on the environment
by people. This is significant as per capita consumption
is increasing even more rapidly than population due to expanding
trade and technology. As Catton (1986) observes: "The world
is being required to accommodate not just more people, but effectively
`larger' people . . ." For example, in 1790 the estimated
average daily energy consumption by Americans was 11,000 kcal.
By 1980, this had increased almost twenty-fold to 210,000 kcal/day
(Catton 1986).
In a finite world, economic assessments of the
human condition need to be based on, or at least informed by,
ecological and biophysical analyses. Appropriate ecological analyses
should focus on the flows of available energy/matter particularly
from primary producers (at a most basic level green plants and
other photosynthesisers) to sequential levels of consumer organisms
in ecosystems (specifically, humans and their economies) and on
the return flows of degraded energy and material (wastes) back
to the ecosystem.
A fundamental question for ecological
economics, therefore, is whether the physical output of remaining
species populations, ecosystems, and related biophysical processes
(ie critical self-producing natural capital stocks) and the waste
assimilation capacity of the ecosphere, are adequate to sustain
the anticipated load of the human economy into the future while
simultaneously maintaining the general life support functions
of the ecosphere. This "fundamental question" is at
the heart of ecological carrying capacity but is virtually ignored
by mainstream analyses and economics. "Quality of life"
over mere survival, as well as moral and ethical considerations,
means that we need to go further and protect all species for intrinsic,
cultural and spiritual reasons as well as functional ones. This
recognised through the Convention on Biological Diversity and
the 2010 biodiversity target.
The interaction of ecological, economic, and
social factors is complex with the disruption of ecosystems having
economic and social consequences as well as fundamental changes
in the economic and social subsystems leading to changes in the
ecosystem. However, there is still a general lack of knowledge
regarding ecosystem functioning and ecological limits to economic
and social activity (ie carrying capacity). Greater research is
needed in this sphere, particularly in relation to international
development and degradation of the tropics, which represent some
of the most biodiverse areas in the world.
In light of this lack of knowledge, the precautionary
principle*, as set out in Agenda 21, and its use to guide policy
and action becomes fundamentally important.
*Definition of the Precautionary Principle:
Where there are threats of serious or irreversible damage, lack
of full scientific certainty should not be used as a reason for
postponing cost-effective measures to prevent environmental degradation.
(Agenda 21, Principle 15).
It asserts there is a "premium" on
a cautious and conservative approach to human interventions in
the natural environment where our understanding of the likely
consequences is limited and there are threats of serious or irreversible
damage to natural systems and processes. (As noted by Myers 1993
in Barbier, Burgess and Folke 1994, 172).
References:
Revisiting Carrying Capacity: Area-Based Indicators
of Sustainability, W E Rees, The University of British Columbia,
1996
Carrying Capacity, M Roy, IISD, 1995
July 2004
62 Please also see supplementary memorandum, Ev. Back
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