I ended the last lecture with a "quick demonstration" of why global change often requires global analysis. That is because systems are linked in a biophysicochemical sense and in a biophysicochemical-socioeconomic sense.

Recall the BOX model (Model - a representation of something; something constructed so as to resemble the truth, but is not the whole truth; could be conceptual, mathematical, etc.):

In the example, the atmosphere is one such box; even though it can be further partitioned in several sub-boxes (stratosphere, troposphere), the scale of analysis of movement/exchange/flow of certain COMPONENTS says it is adequate to treat the whole thing as a box. In such an analysis, we are not concerning ourselves with what happens inside the box, only what is transferred to and from that box.

On the other hand, we treated each and every sedimentary component as a box, even though they are physically admixed as the solid bottom of the ocean. We did so because it is what is required by our mass balance analysis (what we wanted to see/show is how each of these sedimentary components change as a function of changes in other 'reservoirs' in the system.

Recall therefore that we showed the growth of the biosphere (massive draw-down of CO2 from the atmosphere and transfer to biomass that are buried as peat bogs) led to massive deposition of Ca sulfate as evaporites. Not something very obviously related unless you think of the Earth as a whole system that (see Schelesinger, Figure 1.1 - for amplification).

Something that I forgot to point out last time is when you look at Figure 1.2 (Schelesinger, Figure 1.2), you saw the "parallel" changes through time. If we were to look at a longer record, these parallel change will go up and down, or "wiggle" through time. These wiggles constitute what we call temporal cycles, and this is yet another concept I want you to be familiar with.

The above type of analysis is something that you will see time and time again in this course. The theme of linkages and inter-relationships of various reservoirs. Indeed, what I would like to do is to use this framework of RESERVOIRS and flow of material or energy even when we speak of human dimensions of change.

I gave you a handout that attempts to frame the human dimension of environmental change in such a framework of reservoirs (stocks) and processes and flow. That diagram was borrowed from a report called: Human Activity and The Environment, 1994, Statistics Canada (QH541 H85 1994 (ISBN 0-660-15439-0) (Catalogue 11-509E).

This framework is a difficult one to construct, and is something missed (and still missing) from many analysis of Global Environmental Change and Human Dimension of these issues.

In a way, the kind of biogeophysicochemical model I spoke about is a mere subset of this one:

EXPLAIN.

Reservoirs <--> Stocks

Two types of processes; (1) Within Stock/Reservoir, (2) Between Stock

Note an oversight: Population input to Economy (labor, policy)

Two types of Natural Assets/Stock/Reservoir - (1) renewable, (2) non-renewable

The Waste Stock was "separated" only to clearly point out Recycling as a viable "reverse flow".

What does it main to impair the availability of natural assets to future generations? If I made the air one degree warmer, did I impair it's use b future air-breathers? What if I added 2 ppm ozone to it?

These are unresolved issues because there are various shades of grey.