Current Methods of Measurement

I spent several days wrestling with a seemingly simple problem to someone who is familiar writing software and making little tables comparing actions, costs, effects. I wanted to create a simple chart showing the different components of a sustainable system theory, and then evaluate each to see what parts they contained and which parts they lacked. Of course, it wasn't done with such a nice summary in the top down style, but rather a wrangling with a topic and wondering what I was really trying to say and do. More frustrating, it wasn't working and I didn't know why. Well, I was attempting to come up with the Sustainability version of the Grand Unified Theory and then show what was lacking in current implementations.

I think I'll start off with a basic list of what I read and study, and try to follow the bottom up path rather than force an instant epiphany. The list below is limited to my own experience, and I will abbreviate "as far as I know" with AFAIK.

Carrying Capacity - how much life will a system support (AFAIK measures one species only)
Ecological Footprint - estimates of open systems production/consumption ability, and when they fail
Solar Energy Joules (SEJ) - estimate of total energy for a system, related to sunlight. Related to eMergy.
Natural Step:
4 System Conditions - basic guiding principles to sustainability
2020 Vision: Indicators - industry specific interpretations of 4 system conditions
Resources Funnel - qualitative comparison between available resources and consumed resources (see carrying capacity and ecological footprint)
SCRI:
Bounded variations in total system energy (early draft July 05) - Similar to SEJ but includes conversion costs, not just 'transformity'
Living Systems Metrics - based on complete living systems, limits of subsystems
Entropy and Energy Slides - thermodynamics thought experiment that will be a critical component of any complete sustainability metric

Carrying capacity is used in population estimates, and most species (wolves hunting moose) will create self limiting behaviors.

Footprint calculations are rather difficult to wrangle with, because there are many estimates and observations combined to form a single aggregate. There is an implicit model in understanding how these estimates and observations interact, but the models are not usually documented. In some cases the source of the estimates is included, and I find this to be highly respectable but rather rare.

SEJ and Emergy by Odum embrace many concepts that eventually become ridden in terminology. Some versions (1998) include tidal power and geothermal energy but others (1996) are restricted solely to sunlight. Natural systems use chemical energy as well (chemosynthesis, usable by many forms of life that also use photosynthesis) but this is not included AFAIK. Human systems can use sunlight, tides, geothermal heat, inertia based wind (Earth rotation), nuclear power and chemical energy as sources of energy. Of these, human activities are currently limited to using sunlight, stored sunlight (fossil fuels), thermal wind (sunlight based wind), and nuclear power. We use chemical power (non fossil fuels) for industrial practices but not to generate electricity directly. Wind systems are being deployed in Denmark on the open ocean, but adoption is low and it is unknown by me if these are thermal currents from sunlight or based on the rotation of the Earth. Complicating the issue, rotation of the Earth causes wind which interacts with thermal currents. (Anyone know a climatologist?)

SEJ and eMergy are related to sustainability because we use available energy to create and function within our environment. I have read several papers and Fair Use excerpts of the textbook, but I have not read enough to feel competent assessing SEJ or Emergy in any meaningful way. The concepts also evolve greatly over time, and sometimes involve concepts like entropy directly or indirectly but not clearly to me.

The 4 Systems Conditions of Natural Step are based on a consensus of scientists including physicists and chemists. They are very 'top down' in nature and express generic ideas which require a great deal of thought and expert knowledge to apply. The laws of thermodynamics are clearly involved and well stated. I am not sure this is a complete system, but it seems impossible to measure given the approach. It is a very simple qualitative metric that can clearly illustrate if some action is in accordance with the 4 systems conditions. ("Is this chemical found in nature? If no: Is this chemical increasing in nature? If yes: don't use it") The deeper systems understanding is very hidden in Natural Step, and many of the core lessons I see stated in other systems are only vaguely hinted at. Some proponents (Natural Step for Business) point to the combination of several very high level concepts and claim that specific recommendations follow from vague descriptions. (e.g. high energy vs low energy states of matter to reduce industrial entropy.) These 4 conditions are referred to as "tree branches" of sustainability and encourage people to not get lost in the "leaves" of specific statistics. I would like to see more of the "tree limbs" presented.

SCRI's systems (my own affiliation) are based around measuring energy, chemical entropy, resources, and primarily Living Systems. Living Systems shows how systems interact, system failure, important variables and parameters, how living systems deal with information overload and other many important aspects to understanding living systems. A systems approach may lead to a more complete understanding and more accurate systems models. A system can be sustainable without such low level information, but without a complete theory of sustainability we won't know.

All of these different methods of measuring sustainability are useful for identifying warnings. Once the warnings are sounded, we need to fix the issues to be sustainable. The Natural Step is probably the best system for sounding off early warnings AFAIK. Living Systems based models are intended to be a low level understanding, but require a great deal of understanding to make the model. Deeper understanding leads to better choices, and we are facing many hard choices.