Mathematics for Sustainability (Part 2)

21 November, 2012

guest post by John Roe

• Michael Blastland and Andrew Dilnot, Commonsense Guide to Understanding Numbers in the News, in Politics, and in Life, Gotham, New York, 2008. (Review at New York Times.)

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!

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:

• John D. Sterman and Linda Booth Sweeney, Understanding public complacency about climate change: adults’ mental models of climate change violate conservation of matter, Climatic Change 80 (2007), 213-238.

John Harte

27 October, 2012

Earlier this week I gave a talk on the Mathematics of Planet Earth at the University of Southern California, and someone there recommended that I look into John Harte’s work on maximum entropy methods in ecology. He works at U.C. Berkeley.

I checked out his website and found that his goals resemble mine: save the planet and understand its ecosystems. He’s a lot further along than I am, since he comes from a long background in ecology while I’ve just recently blundered in from mathematical physics. I can’t really say what I think of his work since I’m just learning about it. But I thought I should point out its existence.

This free book is something a lot of people would find interesting:

• John and Mary Ellen Harte, Cool the Earth, Save the Economy: Solving the Climate Crisis Is EASY, 2008.

EASY? Well, it’s an acronym. Here’s the basic idea of the US-based plan described in this book:

Any proposed energy policy should include these two components:

Technical/Behavioral: What resources and technologies are to be used to supply energy? On the demand side, what technologies and lifestyle changes are being proposed to consumers?

Incentives/Economic Policy: How are the desired supply and demand options to be encouraged or forced? Here the options include taxes, subsidies, regulations, permits, research and development, and education.

And a successful energy policy should satisfy the AAA criteria:

Availability. The climate crisis will rapidly become costly to society if we do not take action expeditiously. We need to adopt now those technologies that are currently available, provided they meet the following two additional criteria:

Affordability. Because of the central role of energy in our society, its cost to consumers should not increase significantly. In fact, a successful energy policy could ultimately save consumers money.

Acceptability. All energy strategies have environmental, land use, and health and safety implications; these must be acceptable to the public. Moreover, while some interest groups will undoubtedly oppose any particular energy policy, political acceptability at a broad scale is necessary.

Our strategy for preventing climate catastrophe and achieving energy independence includes:

Energy Efficient Technology at home and at the workplace. Huge reductions in home energy use can be achieved with available technologies, including more efficient appliances such as refrigerators, water heaters, and light bulbs. Home retrofits and new home design features such as “smart” window coatings, lighter-colored roofs where there are hot summers, better home insulation, and passive solar designs can also reduce energy use. Together, energy efficiency in home and industry can save the U.S. up to approximately half of the energy currently consumed in those sectors, and at no net cost—just by making different choices. Sounds good, doesn’t it?

Automobile Fuel Efficiency. Phase in higher Corporate Average Fuel Economy (CAFE) standards for automobiles, SUVs and light trucks by requiring vehicles to go 35 miles per gallon of gas (mpg) by 2015, 45 mpg by 2020, and 60 mpg by 2030. This would rapidly wipe out our dependence on foreign oil and cut emissions from the vehicle sector by two-thirds. A combination of plug-in hybrid, lighter car body materials, re-design and other innovations could readily achieve these standards. This sounds good, too!

Solar and Wind Energy. Rooftop photovoltaic panels and solar water heating units should be phased in over the next 20 years, with the goal of solar installation on 75% of U.S. homes and commercial buildings by 2030. (Not all roofs receive sufficient sunlight to make solar panels practical for them.) Large wind farms, solar photovoltaic stations, and solar thermal stations should also be phased in so that by 2030, all U.S. electricity demand will be supplied by existing hydroelectric, existing and possibly some new nuclear, and, most importantly, new solar and wind units. This will require investment in expansion of the grid to bring the new supply to the demand, and in research and development to improve overnight storage systems. Achieving this goal would reduce our dependence on coal to practically zero. More good news!

You are part of the answer. Voting wisely for leaders who promote the first three components is one of the most important individual actions one can make. Other actions help, too. Just as molecules make up mountains, individual actions taken collectively have huge impacts. Improved driving skills, automobile maintenance, reusing and recycling, walking and biking, wearing sweaters in winter and light clothing in summer, installing timers on thermostats and insulating houses, carpooling, paying attention to energy efficiency labels on appliances, and many other simple practices and behaviors hugely influence energy consumption. A major education campaign, both in schools for youngsters and by the media for everyone, should be mounted to promote these consumer practices.

No part of EASY can be left out; all parts are closely integrated. Some parts might create much larger changes—for example, more efficient home appliances and automobiles—but all parts are essential. If, for example, we do not achieve the decrease in electricity demand that can be brought about with the E of EASY, then it is extremely doubtful that we could meet our electricity needs with the S of EASY.

It is equally urgent that once we start implementing the plan, we aggressively export it to other major emitting nations. We can reduce our own emissions all we want, but the planet will continue to warm if we can’t convince other major global emitters to reduce their emissions substantially, too.

What EASY will achieve. If no actions are taken to reduce carbon dioxide emissions, in the year 2030 the U.S. will be emitting about 2.2 billion tons of carbon in the form of carbon dioxide. This will be an increase of 25% from today’s emission rate of about 1.75 billion tons per year of carbon. By following the EASY plan, the U.S. share in a global effort to solve the climate crisis (that is, prevent catastrophic warming) will result in U.S emissions of only about 0.4 billion tons of carbon by 2030, which represents a little less than 25% of 2007 carbon dioxide emissions.128 Stated differently, the plan provides a way to eliminate 1.8 billion tons per year of carbon by that date.

We must act urgently: in the 14 months it took us to write this book, atmospheric CO2 levels rose by several billion tons of carbon, and more climatic consequences have been observed. Let’s assume that we conserve our forests and other natural carbon reservoirs at our current levels, as well as maintain our current nuclear and hydroelectric plants (or replace them with more solar and wind generators). Here’s what implementing EASY will achieve, as illustrated by Figure 3.1 on the next page.

Please check out this book and help me figure out if the numbers add up! I could also use help understanding his research, for example:

• John Harte, Maximum Entropy and Ecology: A Theory of Abundance, Distribution, and Energetics, Oxford University Press, Oxford, 2011.

The book is not free but the first chapter is.

This paper looks really interesting too:

• J. Harte, T. Zillio, E. Conlisk and A. B. Smith, Maximum entropy and the state-variable approach to macroecology, Ecology 89 (2008), 2700–-2711.

Again, it’s not freely available—tut tut. Ecologists should follow physicists and make their work free online; if you’re serious about saving the planet you should let everyone know what you’re doing! However, the abstract is visible to all, and of course I can use my academic superpowers to get ahold of the paper for myself:

Abstract: The biodiversity scaling metrics widely studied in macroecology include the species-area relationship (SAR), the scale-dependent species-abundance distribution (SAD), the distribution of masses or metabolic energies of individuals within and across species, the abundance-energy or abundance-mass relationship across species, and the species-level occupancy distributions across space. We propose a theoretical framework for predicting the scaling forms of these and other metrics based on the state-variable concept and an analytical method derived from information theory. In statistical physics, a method of inference based on information entropy results in a complete macro-scale description of classical thermodynamic systems in terms of the state variables volume, temperature, and number of molecules. In analogy, we take the state variables of an ecosystem to be its total area, the total number of species within any specified taxonomic group in that area, the total number of individuals across those species, and the summed metabolic energy rate for all those individuals. In terms solely of ratios of those state variables, and without invoking any specific ecological mechanisms, we show that realistic functional forms for the macroecological metrics listed above are inferred based on information entropy. The Fisher log series SAD emerges naturally from the theory. The SAR is predicted to have negative curvature on a log-log plot, but as the ratio of the number of species to the number of individuals decreases, the SAR becomes better and better approximated by a power law, with the predicted slope z in the range of 0.14-0.20. Using the 3/4 power mass-metabolism scaling relation to relate energy requirements and measured body sizes, the Damuth scaling rule relating mass and abundance is also predicted by the theory. We argue that the predicted forms of the macroecological metrics are in reasonable agreement with the patterns observed from plant census data across habitats and spatial scales. While this is encouraging, given the absence of adjustable fitting parameters in the theory, we further argue that even small discrepancies between data and predictions can help identify ecological mechanisms that influence macroecological patterns.

Mathematics for Sustainability (Part 1)

21 October, 2012

guest post by John Roe

This year, I want to develop a new math course. Nothing surprising in that—it is what math professors do all the time! But usually, when we dream of new courses, we are thinking of small classes of eager graduate students to whom we can explain the latest research ideas. Here, I’m after something a bit different.

The goal will be through a General Education Mathematics course, to enable students to develop the quantitative and qualitative skills needed to reason effectively about environmental and economic sustainability. That’s a lot of long words! Let me unpack a bit:

General Education Mathematics At most universities (including Penn State University, where I teach), every student, whatever their major, has to take one or two “quantitative” courses – this is called the “general education” requirement. I want to reach out to students who are not planning to be mathematicians or scientists, students for whom this may be the last math course they ever take.

quantitative and qualitative skills I want students to be able to work with numbers (“quantitative”)—to be able to get a feeling for scale and size, whether we’re talking about gigatonnes of carbon dioxide, kilowatts of domestic power, or picograms of radioisotopes. But I also want them to get an intuition for the behavior of systems (qualitative), so that the ideas of growth, feedback, oscillation, overshoot and so on become part of their conceptual vocabulary.

to reason effectively A transition to a more sustainable society won’t come about without robust public debate—I want to help students engage effectively in this debate. Shamelessly stealing ideas from Andrew Read’s Science in Our World course, I hope to do this by using an online platform for student presentations. Engaging with this process (which includes commenting on other people’s presentations as well as devising your own) will count seriously in the grading scheme.

environmental and economic sustainability I’d like students to get the idea that there are lots of scales on which one can ask the sustainability question – both time scales (how many years is “sustainable”) and spatial scales. We’ll think about global-scale questions (carbon dioxide emissions being an obvious example) but we’ll try to look at as many examples as possible on a local scale (a single building, the Penn State campus, local agriculture) so that we can engage more directly.

I have been thinking about this plan for a year or more but now it’s time to put it into action. I’ve been in touch with my department head and got a green light to offer this for the first time in Spring 2014. In future posts I will share some more about the structure of the course as it develops. Meanwhile, if anyone has some good suggestions, let me know!

Mathematics of the Environment (Part 1)

4 October, 2012


I’m running a graduate math seminar called here at U. C. Riverside, and here are the slides for the first class:

Mathematics of the Environment, 2 October 2012.

I said a lot of things that aren’t on the slides, so they might be a tad cryptic. I began by showing some graphs everyone should know by heart:

• human population and the history of civilization,

• the history of carbon emissions,

• atmospheric CO2 concentration for the last century or so,

• global average temperatures for the last century or so,

• the melting of the Arctic ice, and

• the longer historical perspective of CO2 concentrations.

You can click on these graphs for more details—there are lots of links in the slides.

Then I posed the question of what mathematicians can do about this. I suggested looking at the birth of written mathematics during the agricultural revolution as a good comparison, since we’re at the start of an equally big revolution now. Have you thought about how Babylonian mathematics was intertwined with the agricultural revolution?

Then, I raised the idea of ‘ecotechnology’ as a goal to strive for, assuming our current civilization doesn’t collapse to the point where it becomes pointless to even try. As an example, I describe the perfect machine for reversing global warming—and show a nice picture of it.

Finally, I began sketching how ecotechnology is related to the mathematics of networks, though this will be a much longer story for later on.

Part of the idea here is that mathematics takes time to have an effect, so mathematicians might as well look ahead a little bit, while politicians, economists, business people and engineers should be doing things that have a big effect soon.

Five Books About Our Future

16 May, 2012

Jordan Peacock has suggested interviewing me for Five Books, a website where people talk about five books they’ve read.

It’s probably going against the point of this site to read books especially for the purpose of getting interviewed about them. But I like the idea of talking about books that paint different visions of our future, and the issues we face. And I may need to read some more to carry out this plan.

So: what are you favorite books on this subject?

I’d like to pick books with different visions, preferably focused on the relatively near-term future, and preferably somewhat plausible—though I don’t expect every book to seem convincing to all reasonable people.

Here are some options that leap to mind.

Whole Earth Discipline

• Stewart Brand, Whole Earth Discipline: An Ecopragmatist Manifesto, Viking Penguin, 2009.

I’ve been meaning to write about this one for a long time! Brand argues that changes in this century will be dominated by global warming, urbanization and biotechnology. He advocates new thinking on topics that traditional environmentalists have rather set negative opinions about, like nuclear power, genetic engineering, and the advantages of urban life. This is on my list for sure.

Limits to Growth

• Donnella Meadows, Jørgen Randers, and Dennis Meadows, Limits to Growth: The 30-Year Update, Chelsea Green Publishing Company, 2004.

Sad to say, I’ve never read the original 1972 book The Limits to Growth—or the 1974 edition which among other things presented a simple computer model of world population, industrialization, pollution, food production and resource depletion. Both the book and the model (called World3) have been much criticized over the years. But recently some have argued its projections—which were intended to illustrate ideas, not predict the future—are not doing so badly:

• Graham Turner, A comparison of The Limits to Growth with thirty years of reality, Commonwealth Scientific and Industrial Research Organisation (CSIRO).

It would be interesting to delve into this highly controversial topic. By the way, the model is now available online:

• Brian Hayes, Limits to Growth.

with an engaging explanation here:

• Brian Hayes, World3, the public beta, Bit-Player: An Amateur’s Look at Computation and Mathematics, 15 April 2012.

It runs on your web-browser, and it’s easy to take a copy for yourself and play around with it.

The Ecotechnic Future

John Michael Greer believes that ‘peak oil’—or more precisely, the slow decline of fossil fuel production—will spell the end to our modern technological civilization. He spells this out here:

• John Michael Greer, The Long Descent, New Society Publishers, 2008.

I haven’t read this book, but I’ve read the sequel, which begins to imagine what comes afterwards:

• John Michael Greer, The Ecotechnic Future, New Society Publishers, 2009.

Here he argues that in the next century or three we will go through a transition through ‘scarcity economies’ to ‘salvage economies’ to sustainable economies that use much less energy than we do now.

Both these books seem to outrage everyone who envisages our future as a story of technological progress continuing more or less along the lines we’ve already staked out.

The Singularity is Near

In the opposite direction, we have:

• Ray Kurzweil, The Singularity is Near, Penguin Books, 2005.

I’ve only read bits of this. According to Wikipedia, the main premises of the book are:

• A technological-evolutionary point known as “the singularity” exists as an achievable goal for humanity. (What exactly does Kurzeil mean by the “the singularity”? I think I know what other people, like Vernor Vinge and Eliezer Yudkowsky, mean by it. But what does he mean?)

• Through a law of accelerating returns, technology is progressing toward the singularity at an exponential rate. (What does in the world does it mean to progress toward a singularity at an exponential rate? I know that Kurzweil provides evidence that lots of things are growing exponentially… but if they keep doing that, that’s not what I’d call a singularity.)

• The functionality of the human brain is quantifiable in terms of technology that we can build in the near future.

• Medical advances make it possible for a significant number of Kurzweil’s generation (Baby Boomers) to live long enough for the exponential growth of technology to intersect and surpass the processing of the human brain.

If you think you know a better book that advocates a roughly similar thesis, let me know.

A Prosperous Way Down

• Howard T. Odum and Elisabeth C. Odum, A Prosperous Way Down: Principles and Policies, Columbia University Press, 2001.

Howard T. Odum is the father of ‘systems ecology’, and developed an interesting graphical language for describing energy flows in ecosystems. According to George Mobus:

In this book he and Elisabeth take on the situation regarding social ecology under the conditions of diminishing energy flows. Taking principles from systems ecology involving systems suffering from the decline of energy (e.g. deciduous forests in fall), showing how such systems have adapted or respond to those conditions, they have applied these to the human social system. The Odums argued that if we humans were wise enough to apply these principles through policy decisions to ourselves, we might find similar ways to adapt with much less suffering than is potentially implied by sudden and drastic social collapse.

This seems to be a more scholarly approach to some of the same issues:

• Howard T. Odum, Environment, Power, and Society for the Twenty-First Century: The Hierarchy of Energy, Columbia U. Press, 2007.


There are plenty of other candidates I know less about. These two seem to be free online:

• Lester Brown, World on the Edge: How to Prevent Environmental and Economic Collapse, W. W. Norton & Company, 2011.

• Richard Heinberg, The End of Growth: Adapting to Our New Economic Reality, New Society Publishers, 2009.

I would really like even more choices—especially books by thoughtful people who do think we can solve the problems confronting us… but do not think all problems will automatically be solved by human ingenuity and leave it to the rest of us to work out the, umm, details.

Personal Rapid Transportation

21 April, 2012

guest post by Todd McKissick

We all can’t wait for High Speed Rail to come to our town. Whether we’re referring to fast traditional trains on wheels (HSR) or those that float down the track on magnetic fields (maglev), this is the 21st Century, so what most people desire is the full featured deal. Anything less is just another compromise. They have been touted now for 40 years that I know of.

But, as usual, it begs the question: is this really the best solution? I’ve found a lot of different solutions and reviewed everyone of them, but only two stand head and shoulders above the rest.

First, let’s look at some of the specifics of what we’re asking for. It runs really fast so there’s lots of possibility of crossing the country in a couple hours. It gets its efficiency mostly from packing lots of cargo into a very efficient vehicle as most trains do. It’s clearly better than getting 25, 60 or 85 passenger-kilometers per liter in a fully loaded airplane, Suburban or Prius. (That’s 65, 140 or 200 passenger-miles per gallon.) As long as it’s comfortable, this is all good stuff.

Unfortunately, to accomplish this, maglev takes a fairly standard sized train and hovers it over a massive rail with thousands of high-powered electromagnets to float this 80+ tonne piece of machinery from one town to another. It accelerates slowly and brakes slowly, unless you want to double the incredible amount of power it uses already. Its rail system consists of hundreds of tons of concrete per 30 meter segment to make the rail and the support beams, and we all know that concrete is horrible for the environment. And lastly, it costs a billion dollars to build each couple miles of the system.

I’m thinking there’s a better way.

To truly combat the automobile, the airplane and other forms of transportation that use lots of fossil fuels, let’s first look at the last mile segment. This is from your door to the store, work or school lobby or even to your friend’s door. Check out this picture from a company called SkyTran.

It’s called Personal Rapid Transit (PRT for short), and it’s courting numerous locations around the world right now. Basically, it’s a small carbon fiber pod that holds two seats and an iPad. This pod hangs from a small rail which then hangs from arms on regular telephone-style poles. At certain locations, a set of steps to a platform is placed to allow people to call for one and hop in. These terminals are cheap enough that they can be placed so that you’re never more than about 2 blocks from one in town or a couple miles in the country. In fact, they can be incorporated into lobbies, shopping malls, schools, sports arenas and even the higher floors of high rises because they are really just a landing to stand on (or ramp for those using wheels). Up to 350 kilogram pallets can be shipped autonomously. The one-way rails pass each other at different elevations so collisions are avoided while off-ramps to terminals simply drop down to a separate rail to stop on. This allows following traffic to continue at full speed while you merge on or off.

Now for the fun stuff. Once you get in and select your destination, it takes you straight to your end destination. Initial speeds are advertised at 70 kilometers per hour (45 mph) for town and 240 km/h (150 mph) for country but the top speed is well over 320 km/h (200 mph). It’s really only limited by wind resistance. This means you can board one at your sidewalk and step directly onto the upper level of a sports stadium 80 miles away in 25 minutes. Need a 2 hour nap before reaching the kids’ house? You’ll have to be farther than 450 kilometers away. When you figure in all the time needed for the various legs required to travel, this is the fastest way to travel any distance between 6 and 600 kilometers. Ya just gotta love avoiding parking at the airport to switch to a plane, because you can get there faster by avoiding the plane altogether—not to mention airport security!

The ride is perfectly smooth and quiet and offers iPad access with wifi support for your own devices. The pods can even be ‘ganged’ for when you have more than two riders (or kids) so that you load your kids in one car, connect it to your car virtually and then follow them to the destination. Along the way, it can switch the order so you can get out first for safety. Each rail has the capacity of a 3-lane freeway. Since the rail is upside down, balancing suspension is not needed because there’s no chance of the pod falling off. In other words, the curves are all banked for the set speed so the passengers feel no side force.

The energy required to operate it is equivalent to getting 85 kilometers per liter (200 mpg) in a loaded car because it is lifting small enough loads to take advantage of ‘passive levitation’. This is a type of maglev that uses drag to levitate the car. This kicks in at about 1 kilometer per hour, raises the car off the wheels, and diminishes to negligible drag once you pass 22 kilometers per hour (14 mph). Coupling this with regenerative braking means that you really only need to provide the energy to push against the wind. In fact a canopy of solar cells over it could power the entire system during rush hour for free. The rail is designed to also incorporate transmission and/or distribution power lines, 3G / WiFi internet connectivity (including backbone and user distribution) and possibly other utility services. A nationwide network installation could reduce US oil imports from 12 mbbl/day to around 3 mbbl, cutting the cost we pay to OPEC from $700B/yr to $175B/yr.

The cost of building such a system is still fairly high at €4.7/km ($10M/mile), but even that’s 1/19th of the cost of most HSR, and it’s and expected to come way down. The cost to the riders for a privately funded system (before profit, of course) is about €0.02/km, or 4 US cents per mile. Compare this to the cost of a personal vehicle which comes in at 14 times more. When you envision the scope this could be implemented, you can see that many targeted communities could do away with roads altogether, and opt for wider bike paths (to accommodate the occasional moving truck) and more nature. Parking lots could be located in cheap real estate areas or eliminated altogether. Delivery trucks could be replaced with individual pallet deliveries directly inside the factory. In short, all deliveries would eliminate the return trip. Cargo sharing could be implemented along with interstate passenger ‘opportunity’ trips for low cost travel for those who can’t afford travel. If there were a public outcry for this system and we decided to install it nationwide, each community could fund a significant chunk of it from existing road funds with no change in taxes. Or private individuals could invest to install it on a for profit basis.

I mapped out my small 12,000 person town, hit all the major points directly and put a terminal within 2 1/2 blocks of every house, for a total price of $160 million. The annual cost to pay it off completely in 10 years would be around $5-6,000 per family before considering the added savings like providing transportation to those in our population that can’t legally drive now. That’s 60% of what people spend on cars today. What better way to help young adults get their lives started without debt? All infrastructure additions can work in parallel with existing roads and utilities and installation time is roughly 2-3 miles of rail per week per crew. You do the math. If there were a global push behind PRT, we could cut our energy dependence, our environmental impact (not to mention the impact on people’s lives) and bring nature back into our communities.

That covers the short range travel but we still have long distance air, rail and international travel to address. Enter Evacuated Tube Transport.

This system suspends a long vacuum tube overhead or under water to guide mini-trains of 6 passengers on extremely high speed, long range trips. By evacuating the entire length of tube, most of the wind drag is removed, allowing it to travel at speeds up to 6,500 kilometers per hour (4,000 mph) with a maximum of 1 g of acceleration in any direction. The ET3 website suggests that intra-state travel will run at around 550 kilometers per hour (allowing for 2.5 kilometer radius u-turns) while the higher speed legs across the country or under the ocean surface can do a loop in a 320 kilometer radius.

A sample trip from L.A. to N.Y. would take 3 minutes to accelerate over the first 160 kilometers, 42 minutes to cruise the middle and 3 more minutes to slow down while capturing the remaining momentum as electrical regeneration.

Of course, riding in a vacuum requires a pod capable of safely withstanding dangerous pressures, but even transoceanic underwater travel poses no problems we don’t already deal with for other causes. It would be worth the ride for just the scenery if there were transparent sides on the tube, but one has to wonder what you could actually see at that speed below sea level. And since a 6 hour trip across the Pacific would not include any stops, there are some obvious human considerations which would need to be dealt with. Even considering these issues, the economics are sound in dollars, resources and energy. As you can see on their page comparing to standard trains, the ET3 system far surpasses even the Skytran for efficient long distance transport. One could only hope for the merger of the two, where you hop in a Skytran car on your corner, zoom straight into a ET3 loading system, jet up to high speed, cross half the globe, reverse the process at some foreign destination and charge $100 on your card, all in a couple hours.

If you think this is is all hype and fairy land, you might want to search around for some of the projects around the world that are reviewing these two little gems. It’s only a lack of popular opinion that’s holding these two back. Let’s make this happen with a little viral support!

How to Cut Carbon Emissions and Save Money

27 January, 2012

McKinsey & Company is a management consulting firm. In 2010 they released this ‘carbon abatement cost curve’ for the whole world:

Click it to see a nice big version. So, they’re claiming:

By 2030 we can cut CO2 emissions about 15 gigatonnes per year while saving lots of money.

By 2030 can cut CO2 emissions by up to 37 gigatonnes per year before the total cost—that is, cost minus savings—becomes positive.

The graph is cute. The vertical axis of the graph says how many euros per tonne it would cost to cut CO2 emissions by 2030 using various measures. The horizontal axis says how many gigatonnes per year we could reduce CO2 emissions using these measures.

So, we get lots of blue rectangles. If a rectangle is below the horizontal axis, its area says how many euros per year we’d save by implementing that measure. If it’s above the axis, its area says how much that measure would cost.

I believe the total blue area below the axis equals the total blue area above the axis. So if we do all these things, the total cost is zero.

37 gigatonnes of CO2 is roughly 10 gigatonnes of carbon: remember, there’s a crucial factor of 3\frac{2}{3} here. In 2004, Pacala and Socolow argued that the world needs to find ways to cut carbon emissions by about 7 gigatonnes/year by 2054 to keep emissions flat until this time. By now we’d need 9 gigatonnes/year.

If so, it seems the measures shown here could keep carbon emissions flat worldwide at no net cost!

But as usual, there are at least a few problems.

Problem 1

Is McKinsey’s analysis correct? I don’t know. Here’s their report, along with some others:

• McKinsey & Company, Impact of the financial crisis on carbon economics: Version 2.1 of the global greenhouse gas abatement cost curve, 2010.

For more details it’s good to read version 2.0:

• McKinsey & Company, Pathways to a low carbon economy: Version 2 of the global greenhouse gas abatement cost curve, 2009.

They’re free if you fill out some forms. But it’s not easy to check these things. Does anyone know papers that try to check McKinsey’s work? I find it’s more fun to study a problem like this after you see two sides of the same story.

Problem 2

I said ‘no net cost’. But if you need to spend a lot of money, the fact that I’m saving a lot doesn’t compensate you. So there’s the nontrivial problem of taking money that’s saved on some measures and making sure it gets spent on others. Here’s where ‘big government’ might be required—which makes some people decide global warming is just a political conspiracy, nyeh-heh-heh.

Is there another way to make the money transfer happen, without top-down authority?

We could still get the job about half-done at a huge savings, of course. McKinsey says we could cut CO2 emissions by 15 gigatonnes per year doing things that only save money. That’s about 4 gigatonnes of carbon per year! We could at least do that.

Problem 3

Keeping carbon emissions flat is not enough. Carbon dioxide, once put in the atmosphere, stays there a long time—though individual molecules come and go. As the saying goes, carbon is forever. (Click that link for more precise information.)

So, even Pacala and Socolow say keeping carbon emissions flat is a mere stopgap before we actually reduce carbon emissions, starting in 2054. But some more recent papers seem to suggest Pacala and Socolow were being overly optimistic.

Of course it depends on how much global warming you’re willing to tolerate! It also depends on lots of other things.

Anyway, this paper claims that if we cut global greenhouse gas emissions in half by 2050 (as compared to what they were in 1990), there’s a 12–45% probability that the world will get at least 2 °C warmer than its temperature before the industrial revolution:

• Malte Meinshausen et al, Greenhouse-gas emission targets for limiting global warming to 2 °C, Nature 458 (2009), 1158–1163.

Abstract: More than 100 countries have adopted a global warming limit of 2 °C or below (relative to pre-industrial levels) as a guiding principle for mitigation efforts to reduce climate change risks, impacts and damages. However, the greenhouse gas (GHG) emissions corresponding to a specified maximum warming are poorly known owing to uncertainties in the carbon cycle and the climate response. Here we provide a comprehensive probabilistic analysis aimed at quantifying GHG emission budgets for the 2000–50 period that would limit warming throughout the twenty-first century to below 2 °C, based on a combination of published distributions of climate system properties and observational constraints. We show that, for the chosen class of emission scenarios, both cumulative emissions up to 2050 and emission levels in 2050 are robust indicators of the probability that twenty-first century warming will not exceed 2 °C relative to pre-industrial temperatures.

Limiting cumulative CO2 emissions over 2000–50 to 1,000 Gt CO2 yields a 25% probability of warming exceeding 2 °C—and a limit of 1,440 Gt CO2 yields a 50% probability—given a representative estimate of the distribution of climate system properties. As known 2000–06 CO2 emissions were 234 Gt CO2, less than half the proven economically recoverable oil, gas and coal reserves can still be emitted up to 2050 to achieve such a goal. Recent G8 Communiques envisage halved global GHG emissions by 2050, for which we estimate a 12–45% probability of exceeding 2 °C—assuming 1990 as emission base year and a range of published climate sensitivity distributions. Emissions levels in 2020 are a less robust indicator, but for the scenarios considered, the probability of exceeding 2 °C rises to 53–87% if global GHG emissions are still more than 25% above 2000 levels in 2020.

This paper says we’re basically doomed to suffer unless we revamp society:

• Ted Trainer, Can renewables etc. solve the greenhouse problem? The negative case, Energy Policy 38 (2010), 4107–4114.

Abstract: Virtually all current discussion of climate change and energy problems proceeds on the assumption that technical solutions are possible within basically affluent-consumer societies. There is however a substantial case that this assumption is mistaken. This case derives from a consideration of the scale of the tasks and of the limits of non-carbon energy sources, focusing especially on the need for redundant capacity in winter. The first line of argument is to do with the extremely high capital cost of the supply system that would be required, and the second is to do with the problems set by the intermittency of renewable sources. It is concluded that the general climate change and energy problem cannot be solved without large scale reductions in rates of economic production and consumption, and therefore without transition to fundamentally different social structures and systems.

It’s worth reading because it uses actual numbers, not just hand-waving. But it seeks much more than keeping carbon emissions flat until 2050; that’s one reason for the dire conclusions.

It’s worth noting this rebuttal, which says that everything about Trainer’s paper is fine except a premature dismissal of nuclear power:

• Barry Brook, Could nuclear fission energy, etc., solve the greenhouse problem? The affirmative case, Energy Policy, available online 16 December 2011.

To get your hands on Brook’s paper you either need a subscription or you need to email him. You can do that starting from his blog article about the paper… which is definitely worth reading:

• Barry Brook, Could nuclear fission energy, etc., solve the greenhouse problem? The affirmative case, BraveNewClimate, 14 January 2012.

According to Brook, we can keep global warming from getting too bad if we get really serious about nuclear power.

Of course, these three papers are just a few of many. I’m still trying to sift through the information and figure out what’s really going on. It’s hard. It may be impossible. But McKinsey’s list of ways to cut carbon emissions and save money points to some things we start doing right now.

I, Robot

24 January, 2012

On 13 February 2012, I will give a talk at Google in the form of a robot. I will look like this:

My talk will be about “Energy, the Environment and What We Can Do.” Since I think we should cut unnecessary travel, I decided to stay here in Singapore and use a telepresence robot instead of flying to California.

I thank Mike Stay for arranging this at Google, and I especially thank Trevor Blackwell and everyone else at Anybots for letting me use one of their robots!

I believe Google will film this event and make a video available. But I hope reporters attend, because it should be fun, and I plan to describe some ways we can slash carbon emissions.

More detail: I will give this talk at 4 pm Monday, February 13, 2012 in the Paramaribo Room on the Google campus (Building 42, Floor 2). Visitors and reporters are invited, but they need to check in at the main visitor’s lounge in Building 43, and they’ll need to be escorted to and from the talk, so someone will pick them up 10 or 15 minutes before the talk starts.

Energy, the Environment and What We Can Do

Abstract: Our heavy reliance on fossil fuels is causing two serious problems: global warming, and the decline of cheaply available oil reserves. Unfortunately the second problem will not cancel out the first. Each one individually seems extremely hard to solve, and taken
together they demand a major worldwide effort starting now. After an overview of these problems, we turn to the question: what can we do about them?

I also need help from all of you reading this! I want to talk about solutions, not just problems—and given my audience, and the political deadlock in the US, I especially want to talk about innovative solutions that come from individuals and companies, not governments.

Can changing whole systems produce massive cuts in carbon emissions, in a way that spreads virally rather than being imposed through top-down directives? It’s possible. Curtis Faith has some inspiring thoughts on this:

I’ve been looking on various transportation and energy and environment issues for more than 5 years, and almost no one gets the idea that we can radically reduce consumption if we look at the complete systems. In economic terms, we currently have a suboptimal Nash Equilibrium with a diminishing pie when an optimal expanding pie equilibrium is possible. Just tossing around ideas a a very high level with back of the envelope estimates we can get orders of magnitude improvements with systemic changes that will make people’s lives better if we can loosen up the grip of the big corporations and government.

To borrow a physics analogy, the Nash Equilibrium is a bit like a multi-dimensional metastable state where the system is locked into a high energy configuration and any local attempts to make the change revert to the higher energy configuration locally, so it would require sufficient energy or energy in exactly the right form to move all the different metastable states off their equilibrium either simultaneously or in a cascade.

Ideally, we find the right set of systemic economic changes that can have a cascade effect, so that they are locally systemically optimal and can compete more effectively within the larger system where the Nash Equilibrium dominates. I hope I haven’t mixed up too many terms from too many fields and confused things. These terms all have overlapping and sometimes very different meaning in the different contexts as I’m sure is true even within math and science.

One great example is transportation. We assume we need electric cars or biofuel or some such thing. But the very assumption that a car is necessary is flawed. Why do people want cars? Give them a better alternative and they’ll stop wanting cars. Now, what that might be? Public transportation? No. All the money spent building a 2,000 kg vehicle to accelerate and decelerate a few hundred kg and then to replace that vehicle on a regular basis can be saved if we eliminate the need for cars.

The best alternative to cars is walking, or walking on inclined pathways up and down so we get exercise. Why don’t people walk? Not because they don’t want to but because our cities and towns have optimized for cars. Create walkable neighborhoods and give people jobs near their home and you eliminate the need for cars. I live in Savannah, GA in a very tiny place. I never use the car. Perhaps 5 miles a week. And even that wouldn’t be necessary with the right supplemental business structures to provide services more efficiently.

Or electricity for A/C. Everyone lives isolated in structures that are very inefficient to heat. Large community structures could be air conditioned naturally using various techniques and that could cut electricity demand by 50% for neighborhoods. Shade trees are better than insulation.

Or how about moving virtually entire cities to cooler climates during the hot months? That is what people used to do. Take a train North for the summer. If the destinations are low-resource destinations, this can be a huge reduction for the city. Again, getting to this state is hard without changing a lot of parts together.

These problems are not technical, or political, they are economic. We need the economic systems that support these alternatives. People want them. We’ll all be happier and use far less resources (and money). The economic system needs to be changed, and that isn’t going to happen with politics, it will happen with economic innovation. We tend to think of our current models as the way things are, but they aren’t. Most of the status quo is comprised of human inventions, money, fractional reserve banking, corporations, etc. They all brought specific improvements that made them more effective at the time they were introduce because of the conditions during those times. Our times too are different. Some new models will work much better for solving our current problems.

Your idea really starts to address the reason why people fly unnecessarily. This change in perspective is important. What if we went back to sailing ships? And instead of flying we took long leisurely educational seminar cruises on modern versions of sail yachts? What if we improved our trains? But we need to start from scratch and design new systems so they work together effectively. Why are we stuck with models of cities based on the 19th-century norms?

We aren’t, but too many people think we are because the scope of their job or academic career is just the piece of a system, not the system itself.

System level design thinking is the key to making the difference we need. Changes to the complete systems can have order of magnitude improvements. Changes to the parts will have us fighting for tens of percentages.

Do you know good references on ideas like this—preferably with actual numbers? I’ve done some research, but I feel I must be missing a lot of things.

This book, for example, is interesting:

• Michael Peters, Shane Fudge and Tim Jackson, editors, Low Carbon Communities: Imaginative Approaches to Combating Climate Change Locally, Edward Elgar Publishing Group, Cheltenham, UK, 2010.

but I wish it had more numbers on how much carbon emissions were cut by some of the projects they describe: Energy Conscious Households in Action, the HadLOW CARBON Community, the Transition Network, and so on.

Azimuth on Google Plus (Part 5)

1 January, 2012

Happy New Year! I’m back from Laos. Here are seven items, mostly from the Azimuth Circle on Google Plus:

1) Phil Libin is the boss of a Silicon Valley startup. When he’s off travelling, he uses a telepresence robot to keep an eye on things. It looks like a stick figure on wheels. Its bulbous head has two eyes, which are actually a camera and a laser. On its forehead is a screen, where you can see Libin’s face. It’s made by a company called Anybots, and it costs just $15,000.

I predict that within my life we’ll be using things like this to radically cut travel costs and carbon emissions for business and for conferences. It seems weird now, but so did telephones. Future models will be better to look at. But let’s try it soon!

• Laura Sydell No excuses: robots put you in two places at once, Weekend Edition Saturday, 31 December 2011.

Bruce Bartlett and I are already planning for me to use telepresence to give a lecture on mathematics and the environment at Stellenbosch University in South Africa. But we’d been planning to use old-fashioned videoconferencing technology.

Anybots is located in Mountain View, California. That’s near Google’s main campus. Can anyone help me set up a talk on energy and the environment at Google, where I use an Anybot?

(Or, for that matter, anywhere else around there?)

2) A study claims to have found a correlation between weather and the day of the week! The claim is that there are more tornados and hailstorms in the eastern USA during weekdays. One possible mechanism could be that aerosols from car exhaust help seed clouds.

I make no claims that this study is correct. But at the very least, it would be interesting to examine their use of statistics and see if it’s convincing or flawed:

• Thomas Bell and Daniel Rosenfeld, Why do tornados and hailstorms rest on weekends?, Journal of Geophysical Research 116 (2011), D20211.

Abstract. This study shows for the first time statistical evidence that when anthropogenic aerosols over the eastern United States during summertime are at their weekly mid-week peak, tornado and hailstorm activity there is also near its weekly maximum. The weekly cycle in summertime storm activity for 1995–2009 was found to be statistically significant and unlikely to be due to natural variability. It correlates well with previously observed weekly cycles of other measures of storm activity. The pattern of variability supports the hypothesis that air pollution aerosols invigorate deep convective clouds in a moist, unstable atmosphere, to the extent of inducing production of large hailstones and tornados. This is caused by the effect of aerosols on cloud drop nucleation, making cloud drops smaller and hydrometeors larger. According to simulations, the larger ice hydrometeors contribute to more hail. The reduced evaporation from the larger hydrometeors produces weaker cold pools. Simulations have shown that too cold and fast-expanding pools inhibit the formation of tornados. The statistical observations suggest that this might be the mechanism by which the weekly modulation in pollution aerosols is causing the weekly cycle in severe convective storms during summer over the eastern United States. Although we focus here on the role of aerosols, they are not a primary atmospheric driver of tornados and hailstorms but rather modulate them in certain conditions.

Here’s a discussion of it:

• Bob Yirka, New research may explain why serious thunderstorms and tornados are less prevalent on the weekends, PhysOrg, 22 December 2011.

3) And if you like to check how people use statistics, here’s a paper that would be incredibly important if its findings were correct:

• Joseph J. Mangano and Janette D. Sherman, An unexpected mortality increase in the United States follows arrival of the radioactive plume from Fukushima: is there a correlation?, International Journal of Health Services 42 (2012), 47–64.

The title has a question mark in it, but it’s been cited in very dramatic terms in many places, for example this video entitled “Peer reviewed study shows 14,000 U.S. deaths from Fukushima”:

Starting at 1:31 you’ll see an interview with one of the paper’s authors, Janette Sherman.

14,000 deaths in the US due to Fukushima? Wow! How did they get that figure? This quote from the paper explains how:

During weeks 12 to 25 [after the Fukushima disaster began], total deaths in 119 U.S. cities increased from 148,395 (2010) to 155,015 (2011), or 4.46 percent. This was nearly double the 2.34 percent rise in total deaths (142,006 to 145,324) in 104 cities for the prior 14 weeks, significant at p < 0.000001 (Table 2). This difference between actual and expected changes of +2.12 percentage points (+4.46% – 2.34%) translates to 3,286 “excess” deaths (155,015 × 0.0212) nationwide. Assuming a total of 2,450,000 U.S. deaths will occur in 2011 (47,115 per week), then 23.5 percent of deaths are reported (155,015/14 = 11,073, or 23.5% of 47,115). Dividing 3,286 by 23.5 percent yields a projected 13,983 excess U.S. deaths in weeks 12 to 25 of 2011.

Hmm. Can you think of some potential problems with this analysis?

In the interview, Janette Sherman also mentions increased death rates of children in British Columbia. Here’s the evidence the paper presents for that:

Shortly after the report [another paper by the authors] was issued, officials from British Columbia, Canada, proximate to the northwestern United States, announced that 21 residents had died of sudden infant death syndrome (SIDS) in the first half of 2011, compared with 16 SIDS deaths in all of the prior year. Moreover, the number of deaths from SIDS rose from 1 to 10 in the months of March, April, May, and June 2011, after Fukushima fallout arrived, compared with the same period in 2010. While officials could not offer any explanation for the abrupt increase, it coincides with our findings in the Pacific Northwest.

4) For the first time in 87 years, a wild gray wolf was spotted in California:

• Stephen Messenger, First gray wolf in 80 years enters California, Treehugger, 29 December 2011.

Researchers have been tracking this juvenile male using a GPS-enabled collar since it departed northern Oregon. In just a few weeks, it walked some 730 miles to California. It was last seen surfing off Malibu. Here is a photograph:

5) George Musser left the Centre for Quantum Technologies and returned to New Jersey, but not before writing a nice blog article explaining how the GRACE satellite uses the Earth’s gravitational field to measure the melting of glaciers:

• George Musser, Melting glaciers muck up Earth’s gravitational field, Scientific American, 22 December 2011.

6) The American Physical Society has started a new group: a Topical Group on the Physics of Climate! If you’re a member of the APS, and care about climate issues, you should join this.

7) Finally, here’s a cool picture taken in the Gulf of Alaska by Kent Smith:

He believes this was caused by fresher water meeting more salty water, but it doesn’t sounds like he’s sure. Can anyone figure out what’s going on? The foam where the waters meet is especially intriguing.

What’s Up With Solar Power?

13 December, 2011

What’s going on with solar power? On the one hand, I read things like this:

• Paul Krugman, Here comes the sun, New York Times, 6 November 2011.

In fact, progress in solar panels has been so dramatic and sustained that, as a blog post at Scientific American put it, “there’s now frequent talk of a ‘Moore’s law’ in solar energy,” with prices adjusted for inflation falling around 7 percent a year.

This has already led to rapid growth in solar installations, but even more change may be just around the corner. If the downward trend continues–and if anything it seems to be accelerating—we’re just a few years from the point at which electricity from solar panels becomes cheaper than electricity generated by burning coal.

This would be a big deal! As you may have noticed, attempted political remedies for global warming aren’t working too well yet. Cheap solar power won’t be enough to solve the problem: even if we can build a grid that deals with the intermittency of solar power, the problem is that electric power only accounts for some of the fossil fuel burnt. But it could help.

On the other hand, I read things like this:

• Jackie Chang, Half of China solar firms halt production, says report, Digitimes, 9 December 2011.

About 50% of the firms in China’s solar industry have suspended production, according to the country’s Guangzhou Daily.

The daily cited the solar energy division of CSG Holding as claiming that half of the solar firms have stopped production, 30% have halved their output and 20% are trying to maintain certain levels of production.

Digitimes Research’s findings have indicated that only tier-one solar firms in China had capacity utilization rates over 80% in the first half of 2011 while tier-two and tier-three firms were already facing falling capacity utilization rates.

Guangzhou Daily stated that oversupply and significant price drops are the reasons for the firms to shut down production.

The report also indicated that China firms have been facing increasing production costs following news on September 2011 that one of the large-size solar players had a chemical leak at one of its plants that polluted a nearby river. This means the other solar firms now face increasing costs to prevent such pollution while suffering from sharp price drops and low demand.

And this:

• Yuliya Chernova, Chinese solar industry fueled by unsustainable debt, analysts say, Wall Street Journal, 8 December 2011.

Even now, as the U.S. reevaluates its federal loan and other subsidy programs for renewable energy, some lawmakers invoke the strong support the Chinese government offers to its own renewable energy industry as a call for the U.S. to match up with its own support.

Indeed, easy access to low-interest loans over the past three years helped Chinese solar makers build up capacity, and quickly take over market share from European and U.S. manufacturers. In 2010 alone, the China Development Bank made $35 billion in low-interest credit available to Chinese renewable energy companies, according to Bloomberg New Energy Finance, a figure cited by Energy Secretary Steven Chu in his testimony to the House Energy and Commerce Committee in mid-November.

But, perhaps an unintended consequence of this easy access to capital was that the cheap, plentiful production of solar panels resulted in a cutthroat pricing competition, which, in turn is now starting to suffocate the very same large, leading Chinese manufacturers.

“We remain concerned about debt levels across the solar manufacturing complex given the compression of profit margins,” wrote Think Equity analysts in a recent report. “With increasing net debt and reduced module prices, it is hard to imagine absolute gross margin dollars growing enough to offset existing OpEx and interest payments.”

It’s hard to know who to trust. Of course all three of these news reports could be true! Or none.

Do you know what’s really going on with solar power?


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