A course I'd like to teach

Tonight I am going to do something a little different. Rather than a mini-essay, I am going to present the syllabus for a course that I think would be fun to teach someday. In keeping with the spirit of the blog, it is a first pass not a finished product.

Introduction to the Science of the Environment

I. Introduction to Scientific Thinking (2 weeks)

• Brief history of Cosmology
  
• The Calculus
  
• Kuhn, Popper, Feyerbend (or why the extreme postmodern doesn't matter)
  
• Reductionism and Determinism
  

II. Cycles and Systems (4 weeks)

• Rocks (how old is Earth and how do we know?)
  
• Hydrologic Cycle
  
• Ocean and Atmospheric Circulation
  
• Carbon & Nitrogen Cycles
  
• Industrial Ecology
  

III. Models (1 week)

• Conceptual models
  
• Analytic models
  
• Comuter models
  
• Data, Models and Results (chickens and eggs)
  

Review and Mid-term exam

IV. Introduction to Ecosystems (2 weeks)

• Trophic structures
  
• The work of the Odum Brothers (energy flows through natural systems)
  
• Types and Distributions
  
• Urban Metabolism and Ecologic Footprints
  

V. Introduction to Public Health (3 Weeks)

• Aggregate vs Individual health
  
• Toxicology
  
• Epidemiology
  

Begin Aside
This is a topic that could use some more thought. Clearly it is the one I am least familiar with.
End Aside

VI. Wrap up / Tie it all together (1 week)

Final Paper - Write an intellectual history of a major environmental concept (chosen from a list e.g. Sanitation, Clean Air, Climate Change etc.)

Systems, Systems, Systems

In my "Name Change" entry a few days ago I wrote about singular vs plural Earth systems. But what is all this noise about systems? What makes "systems thinking" so important?

Systems thinking is usually contrasted with reductionism. Reductionism is the mode of inquiry that has taught us most of what we know about how Earth works. A reductionist approach to a problem considers the problem in isolation from all other problems and influences. It takes the problem apart bit by bit and then takes the bits apart (turtles the rest of the way down). At the heart of a reductionist approach to learning is the assumption that if all of the bits are understood, then the whole will also be understood. Just as it isolates the problem, the reductionist approach isolates the understanding of each of the component bits from each other (OK - I am bashing a bit here, but as I noted early on, I do that sometimes). Reductionism works well to the extent that problems and bits are actually fairly isolated from each other and that understanding of the bits in isolation is neatly related to the understanding of the bit when it is put back into the whole.

However when bits interact with other bits in non-linear (unexpected / interesting) ways in the context of the whole, then reductionism does not work as well as a mode of inquiry because understanding the bits in isolation only tells you about its behavior in isolation. It doesn't tell you the complete story of how the bit contributes to the function of the complete (here it comes...) system.

So systems thinking is an effort to understand problems in their entirety complete with all of the messy interactions among bits. I sometimes think of the systems approach being one which considers a problem from the perspective of black boxes. Where in a reductionist approach one would relentlessly deconstruct the boxes, a systems approach focuses on the function of the box. How does the box transform a given input into an output? Where does the box get its inputs? Where does a box send its output? The detail of how the box transforms an input into an output is ignored in favor of understanding the interconnection of black boxes and the transformation of signals as they move through the system.

Now clearly systems can have subsystems. (I really must write get the hierarchy thread started soon!) And deconstructing a system into subsystems definitely has a reductionist quality to it. I tend to think that one of the fundamental differences is that reductionism has an inherent assumption of linearity underlying it. In a reductionist frame, the bits have to go back together again in such a way that what you learned in isolation is still the dominant thing to be known, this seems to obviate any cross terms or feedback relationships. In a systems approach it is not assumed that the role of any box can be understood completely on its own. It might be useful to send signals through a box in isolation in order to understand its transforming properties, but by keeping track of and focusing on connections in a systems approach, the "putting back together" problem is always under consideration.

Begin Aside
If any one is actually reading this, I would love some feedback on my equating reductionism with linearity!
End Aside

So wrapping up for tonight - Reductionism has taught us a lot about how the world works and it will teach us more. But by adding a strong measure of systems work to our knowledge producing endeavors, we can gain an richer understanding of problems by focusing on interactions among subjects of interest.

The Grey Area

It is remarkable that I have gotten this far without introducing the following diagram. I call it a disciplinary map and use it to help me think about how to design interdisciplinary teams to address Earth systems problems.

Earth Systems Disciplinary Map

The traditional disciplinary organization of the university is represented by the lobes in the figure. My own discipline, geophysics, maps into the blue lobe along with the other physical sciences such as physics and chemistry. The magenta lobe represents the life science which primarily are biology and medicine. These two lobes together make up what is traditionally thought of as the Natural sciences. The yellow lobe labeled "Human Processes" is the region of Simon's artificial and contains the social sciences, engineering and the humanities. At the intersections of the main lobes are regions that represent interdisciplinary enterprises. Of particular notice is that I map ecology into the purple region between physical and biological processes.

Begin Aside
Exercise for the reader: Where does mathematics map?
End Aside

An example of how problems might progress through the diagram as we learn more about how Earth works is provided by climate change. The problem of increasing CO2 concentration in the atmosphere was first noticed by atmospheric chemists (blue lobe). Understanding the resulting greenhouse warming requires understanding both the CO2 chemistry of the atmosphere and the human processes associated with fossil fuel burning (yellow lobe) and thus maps into the green region. Continuing on with the problem to understand the resulting impacts and the carbon system as a whole requires that we also understand the biological systems that sequester and otherwise move carbon around; this is an Earth systems problem and maps into the grey area.


As you move from the edges of the diagram to the center, interactions among process studied by different disciplines become increasingly important. As we progress we need to work in all regions of the diagram, but as human impacts on the functioning of Earth systems become increasingly important, we must pay increasing attention to the grey areas.

Natural and Artificial

The Natural and The Artificial

Herbert Simon makes a distinction between the Natural and the Artificial
that I have found useful over the years. To first cut, the Natural is
everything that can be separated from human intentionality and the
Artificial is that which reflects human intentionality. In more detail:

Artificial things are synthesized by humans

Artificial things may imitate appearances of natural things

Artificial things can be characterized in terms of functions, goals,
adaptation

Artificial things are often discussed, particularly when they are being
designed, in terms of imperatives as well as descriptives

Natural things are everything that is leftover


Over the last several decades the Artificial has encroached steadily on the
Natural. It is sometimes stated that there are no ecosystems on Earth that
are untouched by Human influence (indeed to the extent that those systems
have plants that have physiological response to the concentration of CO2 in
the atmosphere, this statement must be true). But untouched does not imply
that the systems themselves are now artificial; the details of their
function may be changed, but it is still independent of human
intentionality. That distinction and argument is fairly straight forward in
the Arctic, but what about in Manhattan?

As I have thought about the urban environmental systems, I have begun to
question the usefulness of Simon's distinction in such highly engineered
environments. I can not quite convince myself that the Natural has been
completely swamped (after all the winds still obey the laws of fluid
dynamics), but at some level it seems that the distinction has been
thoroughly blurred.

Consider the trophic structure of a city. To what extent does it reflect
human intentionality? The biodiversity is extremely low with a small number
of very hearty species dominating the biomass. Those hearty species depend
in large part on human refuse for their food. Thus we might argue that
while very large parts of the urban ecosystem imitate the appearance of
natural ecosystems (albeit sick ones perhaps), they are in fact synthesized
by humans. The ecosystem of a city is in large part the a by product of the
rest of the city's designed elements. The trophic structure of the NYC
subway is an unintended consequence of the need to move a remarkably large
number of people around a very small and congested environment; it trophic
structure in that environment natural or artificial? In terms of
imperatives, we try to destroy it constantly.

There has been a lot of discussion about whether humans are parts of the
natural system. To my mind that is a question that does not have a useful
answer. Humans are clearly a part of the singular Earth system, but we are
a special part. We have intentionality that is of particular importance to
us. So where there was a time during which humans might consider themselves
apart from nature, we are now increasingly intertwined with nature despite
(or perhaps because) of our efforts to isolate ourselves from the vagaries
of Earth's natural systems.

Wrapping up, I think that it is important that we carry the notion of a
distinction between that which reflects human intentionality and that which
is independent of it, but that we also recognize that that distinction maybe
coming increasingly difficult to discern. This blurring increases the
importance of developing decision-making processes that recognize the
potential for far reaching human impacts on Earth's functioning.