Adventures in Composting

Adventure #1: I took a tour of Penn State's composting and recycling facilities (see badge on left for proof!) Extraordinary to see the variety of sorting, recycling and composting that is going on, which diverts thousands of tons of material each year from the landfill (the whole operation is paid for several times over by the cost savings on landfill fees).  PSU has just started including bins for compostable material into all the dining facilities, and will be extending this initiative more widely.  Compostable waste is collected daily in bags which are also compostable - made of cornstarch and cellulose. It then goes (still in the bags) to huge linear heaps (I think they are called "windrows" - I saw three or four, each easily a hundred feet long) where it is mixed with sawdust and turned several times over a several-week composting period. The heaps run at a high enough temperature to digest all the food waste, even cooked foods and meats.  The final product is screened mechanically and then goes to PSU landscaping.

Adventure #2: For me, this is just an adventure in reading - but for the two students who took it, it was a whole lot more than that.  An entry in the blog of the AASHE (American Association for Sustainability in Higher Education) describes the journey of two students who brought about a major change in their school's waste management policy.  Very refreshing to read about people moving from words to action in this way.

Adventure #3: Installed a compost tumbler in the garage.  (We'll see whether that is the optimal location - it makes unloading kitchen scraps into it very easy, and of course it keeps the temperature high; I'm trying to persuade myself that the "organic" smell in the garage is a pleasant plus, but the clouds of gnats every time I open the tumbler certainly are not.  If things get too bad, the tumbler will have to move outside.)   I grew up in a family that carefully composted kitchen scraps and it feels right  to be doing that again (not to mention making me much more aware of the part of our waste stream that can't be composted or recycled).

Mathematics for Sustainability 3

Limits to Growth: The 30-Year Update: Donella H. Meadows,Jorgen Randers,Dennis L. Meadows: 9781931498586: Amazon.com: Books via kwout

The second of my four themes for the planned "Mathematics and Sustainability" course is "Changing".  I think of this as the core section.  I would like my students to develop some intuitions about stocks and flows, rates of change, and dynamical systems.

In putting this material front and center I am recapitulating an experience which was important for me both as a mathematician and as someone concerned about environmental sustainability: I mean reading, in about 1975, the famous book The Limits to Growth, which had appeared a few years before. The "System Dynamics" models in Limits (basically graphical representations of differential-difference equations) fascinated me.  I built models of my own of similar kinds, and explored them numerically with a hand calculator and (when that failed) through a dial-up link to a minicomputer, a Modular One located at the University of Warwick.  I don't think it is fanciful to see my research interest in "large scale" and "long time" properties as linked to these early numerical experiments.  More relevant to an undergraduate course, though, is the appreciation that this "playing" gave me for the robustness of qualitative descriptions like feedback, overshoot, collapse, oscillation, exponential and resource-constrained growth.  Despite its quantitative focus - inevitably controversial - the basic focus of Limits was, it seems to me, this qualitative one.

In order to help students share this kind of experience I would like to give them the opportunity to build models using a variation of the System Dynamics approach.  Nowadays there are several software packages available that build models directly from the kinds of diagrams that are used to represent system dynamics models.  I am looking at using Insight Maker for the course, because it is free and runs in a web browser.  I hope to have the students develop their own models using Insight Maker and share and comment on each others' models via the course blog.  At the same time I plan to use Insight Maker in class to explain some basic ideas like stocks and flows, exponential and logistic growth; and perhaps we'll construct some models (like an aggregated climate model) using Insight Maker just to show what can be done.

Evaluating student software projects is fraught with pitfalls (at least,so it seems to me) - I think that seeing how the students explain to each other via the blog what it is their models actually accomplish will provide important information about how good a level of understanding they have attained.

Eco-Law and Eco-Gospel

For God has done what the law, weakened by the flesh, could not do. By sending his own Son...he condemned sin in the flesh, in order that the righteous requirement of the law might be fulfilled in us, who walk not according to the flesh but according to the Spirit.

Thus Saint Paul, in the climactic eighth chapter of the letter to the Romans, surely the charter document of "Pauline Christianity".  For seven chapters, he and his readers have wrestled with what he calls the "Law": the revealed moral code which points toward a life of holy integrity.  The Law, comments Paul, has strength indeed to condemn those who go astray (and that is everyone, with Paul at the head of the list), but it has no power to effect what it commands.  So, although it holds out the prospect of a new and fruitful life, all the Law actually achieves is to show us how inextricably we are entangled in a God-defying system of domination (which Paul calls the flesh): the very commandment that promised life proved to be death to me (Rom 7:10)  Moralizing is not enough: the negative externalities of the Law outweigh its positive effects.  Who shall deliver us?

 As I've joined more actively in religious-environmental conversation over the last couple of years, it has struck me how often this dialogue takes the form of the Law. "Thou shalt not...": it would be easy enough to write an eco-Decalogue. In it, sound science and a passion for justice (both of them good things, just as the Law is holy and just and good) would point the believer toward a life of "creational integrity". Fair enough - but we are wary of speaking of any transformation that can bring to effect the commands of this new Law.  And such transformation is needed, if we are to have a hopeful message to share.

In Romans 8, Paul's words are radiant with confidence that transforming power, such power as the Law did not possess, has been unleashed through the coming of Jesus. It is that confidence which propelled him in his extraordinary travels, in his preaching and writing and "sabbaticals" in various jails.  Not a new Law, but a new life.  He is like the man Jesus speaks of in Matthew 13:44, who finds hidden treasure in a field: "then in his joy he goes and sells all he has, and buys the field."

Do we (should we) have an eco-Gospel? A vision for a new way of living that is so attractive that "all you have" is not even a difficult price to pay? A transformed consciousness that empowers human beings to begin to live at peace with creation?  I don't know.  But I think that we sell our faith short if all we believe is that it can make us more effective preachers of eco-Law.  "Ethics interprets the Law as the form of the Gospel" says Barth, "i.e. as the sanctification that comes to humanity through the electing God." (CD II.2, 36, thesis).  I want to interpret the eco-Law as the form of the Gospel too

First law of thermodynamics, dammit!

Here's an example of why we need education in math for sustainability.

The Independent (a major UK newspaper) has an exciting headline today. Exclusive: Pioneering scientists turn fresh air into petrol in massive boost in fight against energy crisis  According to the Independent, this is a " revolutionary technology that promises to solve the energy crisis as well as helping to curb global warming by removing carbon dioxide from the atmosphere."

Well, what have they done? According to the article, "Air Fuel Synthesis in Stockton-on-Tees has produced five litres of petrol since August when it switched on a small refinery that manufactures gasoline from carbon dioxide and water vapor...  'We've taken carbon dioxide from air and hydrogen from water and turned these elements into petrol,' said Peter Harrison, the company's chief executive."  (Petrol=gasoline for you USA types.)

In other words, they have reversed the combustion reaction
2C8H18 (1kg) + 25O2 (3.5kg) -> 16CO2 (3.1kg) + 18H2O (1.4kg) + 48 MJ
that powers our gasoline engines. This is a significant technical achievement (though, if I recall correctly, it is not the first time it has been done: wasn't this demonstrated at Sandia National Laboratories a few years back?)

But to reverse the reaction, we need an input of energy at least equal to the 48 MJ that are released when the reaction runs in the forward direction, that is, when we burn the fuel. (Probably a good deal more, because the process will not be especially efficient.)  In other words, what we have is a process for storing energy in the form of gasoline. This could be useful for some purposes, but it is hardly what is implied by the "turning fresh air into petrol" headline.

Let's see if the article acknowledges this. Sort of. It says, "The process is still in the early developmental stages and needs to take electricity from the national grid to work."  An interesting sentence! Neither clause is false, but many readers will receive the unstated suggestion that a fully developed version of the process would not need an energy input - and that is completely wrong.

I would hope that someone who had taken the "Math for Sustainability" course could read the article, perceive the basic issue that I have outlined above, and do for herself some simple calculations about the amount of (renewable!) energy that the process should draw if it were to have a significant impact on global CO2 levels.

I'd also like Independent journalists to be required to take my course!  Well, one can dream.

When Science is a Conveyor of Bad News

Another excellent and thought-provoking post from Tom Murphy. Here's how he begins: "Science is a phenomenal institution. Sometimes I can’t believe we created this construct that works so incredibly well. It manages to convert human imperfections into a remarkably robust machine that has aided our growth juggernaut. Yet science seeks truth, and sometimes the truth is not what we want to hear. How will we respond? Will we kill the messenger and penalize the scientific institution for what is bound to be an increasing barrage of bad news this century as Earth fills beyond capacity?"

Read the full article here. Please.

PAIPL Annual Meeting

I attended the annual meeting of Pennsylvania Interfaith Power and Light in Harrisburg yesterday.

Rashly, they voted me onto the board.  (Still more rashly, the board then proposed that I serve as Treasurer - I guess they must have supposed that being a math professor had something to do with the ability to do arithmetic accurately).

Keynote speakers were Fletcher Harper from GreenFaith and Richard Alley from Penn State.  Alley is  PSU's Evan Pugh Professor of Geosciences.  (The Evan Pugh title is Penn State's highest honor - there are only 23 Evan Pugh Professors currently active across the whole university, out of a faculty of over 2000.)  He is also the host of the PBS series Earth - The Operators Manual.

Here is a telling video clip from Alley's talk (courtesy of Jon Brockopp).
 

Mathematics for Sustainability 2

The Numbers Game: The Commonsense Guide to Understanding Numbers in the News,in Politics,and inLife: Michael Blastland,Andrew Dilnot: Amazon.com: Books via kwout

In Mathematics for Sustainability 1 I explained that I want to develop a new Gen Ed course "to enable students to develop the quantitative and qualitative skills needed to reason effectively about environmental and economic sustainability".  With this as the general objective, what are some of the specific content areas that the course should address, and what should be the specific objectives within each content area?

Right now, I see four mathematical content areas:

• Measuring
• Changing
• Networking
• Risking

Measuring - using numbers (including "large" and "small" numbers) to get an idea of the size and significance of things.  Including, for instance: physical units, prefixes (mega, giga, nano, and all that), percentages/ratios, estimation, reliability.  That's a list of concepts on the math side but of course the examples should be sustainability focused.  So I'd like the students to be able to answer questions like

• An inch of rain falls over a forest plot of an area 3.21 square miles.  How many tons of water fall? 
• Roughly, what is the total mass of carbon dioxide in the Earth's atmosphere at present?
• Suppose that a nuclear accident spreads 2.3 grams of cesium-137 uniformly over an area of 900 square miles. Compare the radioactivity from this source with the natural background.
• On average, how many gallons of gasoline per second are burned on the Pennsylvania Turnpike?
• A 10-acre farm near State College can produce enough food to support how many people on a vegetarian diet?  On a "standard American" diet?
• Roughly, how many birds do you think there are in the world?   How accurate do you think your estimate is?

 Of course, part of "being able to answer" such questions is being able to know what additional questions to ask in order to give reasonable answers.

I am looking at several books in order to get a handle on this part of the course.  Right now I am reading The Numbers Game by Blastland and Dilnot.  It starts with an arresting example: how many centenarians are there in the US?  That should be easy: just count, right?  In fact, census returns ask people to report their age.  But the self-reported numbers vary wildly and are estimated to be exaggerated by factors of 20 or more in some cases.  Starting from this example, the book seems to give a good overview both of the difficulty and the importance of measuring, both in absolute and relative terms.

Any more suggestions for this part? Thanks!


EDIT: I am thinking now to put the important distinction between stocks and flows in this section too.  (We have to know what we are measuring!)   Logically, it might belong in the Changing section but pedagogically it seems better here.  A reader on Azimuth sent me a link to this interesting paper which points out how important the stock/flow distinction is in public (mis)understanding of the greenhouse effect.