Select Committee on Environmental Audit Written Evidence


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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