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Fairfax Cross County Trail, 41 miles: completed 2 July 2010.
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Category Archives: Climate Change
Not just for coffee farms
Paul Stapleton introduces “evergreen agriculture.” In Africa, intercropping with trees of the genera Sesbania, Gliricidia, Tephrosia, and others improves yields and provides other benefits; dropped leaves from the trees provide natural fertilizer.
The indigenous African acacia (Faidherbia albida) is perhaps the most remarkable of these fertiliser trees. Faidherbia sheds its nitrogen-rich leaves during the early rainy season and remains dormant throughout the crop-growing period. The leaves grow again when the dry season begins. This makes it highly compatible with food crops, because it does not compete with them for light, nutrients or water during the growing season: only its bare branches spread overhead while the food crops grow to maturity.
Weather and Climate term paper
For our term writing project, Dan Ferandez asked us to critique an article and develop “your own personal ideas and conclusions” on the topic of “global climate change.” Since I had recently read a piece about Judith Curry, finding material to write about was easy. Making a positive contribution to the debate was much more difficult.
Bird Phenology Program
Consistent with another of my volunteer gigs (with Recording for the Blind & Dyslexic), I seem to have positioned myself as a wetware information transcriber. A couple of months ago I started working about an hour a week as a data entry volunteer for the North American Bird Phenology Program, based out of Patuxent Wildlife Research Center.
Phenology is the study of comings and goings in the natural world—what day of the year the swallows return to Capistrano, the lilacs last in the dooryard bloom’d, that sort of thing. Decade-to-decade trends in a particular location can provide additional evidence to researchers studying climate patterns, among other things.
There are a number of phenology programs active under the umbrella of the USA National Phenology Network. One of the broadest-scoped citizen science initiatives was organized in 1881 by Wells W. Cooke, and was later expanded by C. Hart Merriam of the newly-formed American Ornithologists’ Union. For 90 years, up to 3,000 field researchers submitted data on the arrivals and departures of migratory birds in North America, in sort of an ornithological Mass Observation Project. Data was collected on 2×5-inch slips; when the project was wound down in 1970 (as other means of collecting similar data evolved), the records base comprised 6 million of them. In 2003, Sam Droege began efforts to safeguard and digitize the slips.
Many of the records are on a GPO-issued form, designated 3-801 or Bi-801; this form was redesigned a couple of times to collect different data. But many more are simply hand-written slips in a particularly compact shorthand that identifies the species (often simply by a three-digit AOU number), the location and observer, and the dates that the bird was first seen in the course of the year; seen again; seen commonly; and last seen during the breeding or migration season.
As you would expect, the transcription of this data from scanned document images into a web form is not an automatable process. Enter the volunteer scribes. It takes me 30 seconds or more to copy out a card—up to several minutes if I have to puzzle out a location name (Google Maps is my BFF) written in faded fountain pen ink in a cursive handwriting style more suited to wedding invitations. The data collection protocol also provides for observer’s notes on whether the bird breeds in the area, is a winter resident, and assessment of abundance (one point on the scale is the quaintly labelled “tolerably common”)—all that, along with any other notes made by the observer, is to be transcribed into fixed fields or free text. Each observer seems to have a different approach to spelling, punctuation, and capitalization. The opportunity for transcription errors is therefore high, so each card is copied into the database twice, then compared.
There’s lots more to be done: the number of digitized cards only numbers in the few hundred thousands, so if you’re into birds or just have some spare cycles, I would encourage you to sign up for the program. You can request to transcribe cards only for a particular location or a particular species, or you can do what I do and just pull cards at random. I’ve copied slips filed from tiny, obscure places like Hadlyme, Connecticut and Rhoma, Texas; I’ve worked with a card prepared by A. W. Schorger, author of the definitive book on the Passenger Pigeon. No particular knowledge of birds is required; in fact, the procedures we follow call for a literal transcription of the record, no interpretation or corrections allowed. So even if I “know” that the common name of a bird has been changed in the past hundred years, my instructions are to copy what the observer wrote, and to let the researchers clean up the data later.
And that turns out to be a learning experience for me, too. Before I started transcribing, I wasn’t aware that Purple Martin (Progne subis) and Eastern Phoebe (Sayronis phoebe) once had simpler names in common use (Martin, Phoebe). And I had never heard of Holboell’s Grebe, which we know now as Red-necked Grebe (Podiceps grisegena).
Droege and his team have already begun to draft papers from the data, especially looking at patterns of Barn Swallow (Hirundo rustica) migrations. The San Francisco-area ABC affiliate put together a rather fine story on the program.
Some links: 44
In a well-done piece, Paul Krugman explains the difference between a carbon tax and cap-and-trade in terms an economist understands, and in terms a politician understands. And while the former might be preferable in economic terms, a cap-and-trade system has a chance of actually happening. And that’s important:
So what I end up with is basically Martin Weitzman’s argument: it’s the nonnegligible probability of utter disaster that should dominate our policy analysis. And that argues for aggressive moves to curb emissions, soon.
Meat pollution
Elizabeth Kirkwood on the very public decision by Britain’s top climate adviser, Nicholas Stern, to stop eating meat as a means of mitigating global warming. Strong stuff:
Why are we not outraged by what the meat industry and those who support it, which is, let’s face it, most of us, is doing to our planet? Why is meat consumption not stigmatised in the way that driving 4×4 gas guzzlers is?
Blog Action Day 2009
In recognition of Blog Action Day 2009, herewith readings and resources for learning more about this complicated subject called “climate change,” one that is full of ramifications and interdependencies.
At Climate Interactive, you will find links to several simplified policy simulations: via animated graphics, you can see the effect of increased afforestation, decreased CO2 emissions by developed countries, and so on. Also find there an overview of C-ROADS (Climate Rapid Overview and Decision-support Simulator), which is designed to be used by policy-makers (not modellers) and runs on a laptop.
Read Johan Rockström et al.’s recent paper for Nature, “A safe operating space for humanity,” along with expert commentary. The paper’s thesis is that global climate change (as measured by radiative forcing [the rate of energy change per unit area of the globe as measured at the top of the atmosphere] as well as atmospheric carbon dioxide) is just one of ten parameters, all of which must be managed into safe operating levels, that are important for the survival of life on the planet.
We propose that human changes to atmospheric CO2 concentrations should not exceed 350 parts per million by volume, and that radiative forcing should not exceed 1 watt per square metre above pre-industrial levels. Transgressing these boundaries will increase the risk of irreversible climate change, such as the loss of major ice sheets, accelerated sea-level rise and abrupt shifts in forest and agricultural systems. Current CO2 concentration stands at 387 p.p.m.v. and the change in radiative forcing is 1.5 W m-2.
By comparison, the carbon dioxide concentration in the atmosphere, pre-Industrial Revolution, was 280 ppm by volume, and the rate of radiative forcing at the beginning of what is now being called the Anthropocene Epoch was zero. The other parameters (keep in mind that most of these are rates of change rather than values) are:
- rate of biodiversity loss;
- nitrogen and phosphorus cycles;
- stratospheric ozone depletion;
- ocean acidification;
- global freshwater use;
- change in land use;
- atmospheric aerosol loading;
- chemical pollution.
The authors find biodiversity loss (as measured by species extinction rate) and N2 removals from the atmosphere for human use running at the most troubling rates. While the pre-industrial era extinction rate was 0.1-1 species per million species per year, the current rate is something like 100, and order of magnitude more than their proposed redline value of 10. The nitrogen situation may be even worse: pre-industrial man removed no net nitrogen from the air. Rockström et al. propose a limit of 35 million tons per year; the current rate is 121 million tons annually.
A recent leader by The Economist explores the political landscape, and in particular the problem of effective transnational agreements to lower carbon emissions. The U.S. Senate must ratify any international treaty that the President enters into. Arguing that the Kyoto protocol failed because it could not get approval of these 100 Americans, nor did excessive emissions by Kyoto signatories actually lead to sanctions, the editorialist writes:
There is an alternative: moving the negotiations onto a different diplomatic track…. Australia has proposed another route. All countries would come up with a “national schedule” of programmes, such as cap-and-trade and low-carbon regulations. Developed countries would also specify an amount by which they mean to reduce their emissions. These commitments would have the force of domestic law, but would not be subject to international sanctions.
Finally, at the softer end of the spectrum, for inspiration and exhortation, take a look at this anthology assembled by the Union of Concerned Scientists: Thoreau’s Legacy: American Stories about Global Warming, 67 pieces of writing and art “drawn from nearly 1,000 submissions about beloved places, animals, plants, people, and activities at risk from a changing climate and the efforts that individuals are making to save what they love,” available both in print and as a handsomely designed Flash-based interactive.
Squeezed in Panama
Elisabeth Rosenthal reports on the controversial findings of Joe Wright, a senior scientist at the Smithsonian Tropical Research Institute in Panama, that the rate of secondary rain forest formation (through abandonment of farms via urbanization, and other causes) is outpacing the rate of primary rain forest destruction. The arguments critical of Wright and those in his support tend to tangle together the function of rain forests as a carbon sink with their role as a refuge for biodiversity.
Regenerated forests in the tropics appear to be especially good at absorbing emissions of carbon, but that ability is based on location and rate of growth. A field abandoned in New York in 1900 will have trees shorter than those growing on a field here [in Central America] that was abandoned just 20 years ago.
For many biologists, a far bigger concern is whether new forests can support the riot of plant and animal species associated with rain forests. Part of the problem is that abandoned farmland is often distant from native rain forest. How does it help Amazonian species threatened by rain-forest destruction in Brazil if secondary forests grow on the outskirts of Panama City?
Here in the East, you can observe the results of old field succession by taking a short drive to the Blue Ridge. Much of the now-protected parkland in the Appalachians was once in agricultural production, as the evidence of a family cemetery in the woods will attest.
Two turkey franks, hold the cheese
In response to “Burgernomics, indeed,” Leta asked me a good question: What’s the difference between eating chicken from a farm in Delaware and fresh broccoli from California’s Central Valley? (We live on the East Coast.) Isn’t trucking all that foliage cross-country less environmentally-friendly? Recent research by Christopher L. Weber and H. Scott Matthews attempts to answer that question. Their results are also discussed in a post by Jane Liaw. In short, Weber and Matthews’ findings are that it comes out the same, but for different reasons.
The Carnegie Mellon researchers looked at the life-cycle impact, from production to retail, in equivalent greenhouse gas (GHG) emissions, for the production of food for consumption in the United States, where food is analyzed as 50 commodities grouped into seven USDA-style categories. They use a methodology, informed by the work of Wassily Leontief, termed input−output life-cycle assessment (IO-LCA). Input-output analysis accounts for the fact that some goods are produced and shipped around only in order to make other goods for final consumption: chickens have to be fed corn that was grown somewhere else, broccoli has to be irrigated with water that has to be piped from somewhere else, and so forth. The approach aggregates across the country, so it’s not going to account for regional differences in production or consumption (compare the work of Colman and Päaster on wine production). Beyond that, I am limited in my ability to critique the methods of the paper.
The first figure that stands out from the paper is 12,000. That’s the number of equivalent ton-kilometers of freight, per household, required to meet food-demand in the U.S. in 1997. You could think of this as a monthly truckload of 1 metric ton of food (and products that went into making the food) travelling 1,000 km (600 miles) around the country, ending up at the supermarket, to feed a “typical family of four.” (The paper omits the “last mile” of transportation from store to home.) But only 25% of that freight mileage is part of the “direct” tier, from farm to retail. The remaining three-fourths is used in intermediate production.
When the numbers are crunched by food category, things get more interesting.
Final delivery (direct t-km) as a proportion of total transportation requirements varied from a low of 9% for red meat to a high of around 50% for fruits/vegetables, reflecting the more extensive supply chains of meat production (i.e., moving feed to animals) compared to human consumption of basic foods such as fruits/vegetables and grains.
But we’ve still got to work out the GHG impact. The researchers assign CO2-equivalences for ten modes of transport, including rail, truck, ocean (by container or bulk), air, and oil and gas pipeline (fertilizer feedstocks gotta get there somehow). Due to transmission losses, natural gas pipelines are only as efficient as trucks.
Once this calculation is made, the relative unimportance of local transport in the total picture begins to emerge.
Total GHG emissions are 8.1 t CO2e/household-yr, meaning delivery accounts for only 4% of total GHG emissions, and transportation as a whole accounts for 11%. Wholesaling and retailing of food account for another 5%, with production of food accounting for the vast majority (83%) of total emissions.
Within food production, which totaled 6.8 t CO2e/household-yr, 3.0 t CO2e (44%) were due to CO2 emissions, with 1.6 t (23%) due to methane, 2.1 t (32%) due to nitrous oxide, and 0.1 t (1%) due to HFCs and other industrial gases. Thus, a majority of food’s climate impact is due to non-CO2 greenhouse gases.
Okay, so what about the chicken-and-broccoli question? The paper presents the relative GHG effect by the seven commodity categories, scaled by weight, retail expenditure, and (most importantly, I believe) calorie content. By any of these measures, red meat comes out with the largest carbon footprint, followed by the milk and cheese category. Scaled by food energy content, the chicken/fish/eggs group matches the fruit and veg group.
The authors’ take-away message is that even a small change in diet can have a significant impact, given some additional reasonable assumptions. Just switching your calories for one day a week out of red meat and dairy and into veggies has the equivalent effect of a completely “localized” consumption habit.
… [but] this is conversely true for households which already exhibit low-GHG eating habits. For these households, freight emissions may be a much higher percentage of the total impacts of food, and especially will be important for fresh produce purchased out of season.
They also consider briefly the upswing in food imports into the U.S. Since ocean transport is relatively efficient (more than ten-to-one better than trucking), they infer that globalization has less of a deleterious effect than some fear.
It’s also worth noting that Weber and Matthews’ work is only concerned with GHG emissions. Other differential impacts on the environment by food category—for instance, land use, water quality, acid rain, noise pollution, and smog—are not part of their analysis.
Burgernomics, indeed
For the current issue of Scientific American, Nathan Fiala summarizes his own work as well as that of Susan Subak concerning the environment impact of producing beef, pork, and chicken—specifically, the contribution of livestock farming to greenhouse gases and hence to climate change. Some of the graphics include gratuitous elements or are poorly conceived, unfortunately something the magazine is becoming known for. But a key chart drives home the point: compared to vegetable production, growing meat makes a much bigger impact. While making a pound of potatoes entails generating 0.13 pound of CO2-equivalent gases, a pound of beef creates 57 times as much, 7.4 pounds of global warming gas. I would have preferred a closer apples-to-apples comparison that matched the various foodstuffs in terms of calories, and one that made it clear whether we’re talking food in the field or cooked, on the plate, but the force of the argument remains.
Fiala references the 2006 report from the UN Food and Agriculture Organization (FAO): Livestock’s Long Shadow. Going beyond livestock’s climate change effects, the report documents meat’s huge environmental footprint:
- Livestock farming covers 30% of the planet’s landmass.
- It is responsible for 18% of worldwide carbon dioxide-equivalent gas emissions, more than that of the transportation sector.
- 8% of global water use goes into beef, chicken, and pork agriculture.
So it’s not surprising that the authors write in the Executive Summary:
The livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global. The findings of this report suggest that it should be a major policy focus when dealing with problems of land degradation, climate change and air pollution, water shortage and water pollution and loss of biodiversity.
Livestock’s contribution to environmental problems is on a massive scale and its potential contribution to their solution is equally large. The impact is so significant that it needs to be addressed with urgency. Major reductions in impact could be achieved at reasonable cost.
A green line
I got a chance to read Tyler Colman and Pablo Päaster’s white paper, “Red, White, and ‘Green’: The Cost of Carbon in the Global Wine Trade,” which is summarized in Colman’s post.
The authors perform a detailed analysis of the carbon footprint (in terms of greenhouse gas emissions) of the production and distribution of a bottle of wine for consumption in the United States. The independent variable in their computations is the location where the wine is produced—Australia, France, Argentina, or California. Although they also analyze the effects of different agricultural practices (organic farming as might be typical in the various regions) and other links in the chain (such as CO2 released by fermentation), it turns out that the predominant carbon contributor is the means of shipping the finished, bottled wine and the distance that it must be shipped. For instance, for delivery to Chicago, a hypothetical 750ml bottle of wine from the Napa Valley produces almost 4.5kg of carbon dioxide; 3kg is accounted for by truck shipment from California. By contrast, wine from France, which is shipped by relatively efficient container ship, produces 2.0kg; and even here, shipping accounts for more than half of the total. The other significant components include the production of bottles, land use, and consumption of oak for in-barrel aging.
The results enable the researchers to draw a “green line” across the Midwest and South: to the east of this line, it’s more emissions-efficient to consume wine shipped from France than trucked from California (or Washington, presumably). Of course, if you’re fortunate enough to live in a state that produces its own drinkable wine (like I do, in Virginia), an even better choice would be the local tipple. Buying by the 1.5l magnum also helps: as they say, “shipping wine is often really about shipping glass with some wine in it.”
Two other asides: First, a footnote gives the nod to the general sustainability of cork as a bottle closure. Second, the writers note that growing grapes requires a lot of water for what you harvest: 1.2 to 2.5 megaliters per hectare, or 550 kiloliters per ton of grapes. This is partly due to the fact that grapes don’t yield a lot of mass per hectare, compared to a crop like corn.
Plant a billion
Herewith my Earth Day project for this year.
(The widget is a little wide, so I’m not sure what to do with it when it scrolls off the bottom of the page.)
Arctic Symposium 2007
As a sort of chaser to Thursday’s post, I want to applaud the ecumenical convocation of world-wide religious leaders at the foot of a melting glacier in Greenland, as reported by ABC News and Reuters. Muslims, Jews, Buddhists, Christians of several stripes, and indigenous people united in a silent “prayer for the planet” as part of an effort to withstand global climate change. The event was part of a weeklong symposium sponsored by Religion, Science, and the Environment, an NGO based in Greece.
Black gold
Dan Charles visits Iowa farmland with soil scientist Lee Burras of Iowa State University. They discuss no-till farming, cover crops, and other organic farming practices as means of carbon sequestration—all of them ways that farmers can have a positive effect on global climate change.
Market signals
Katherine Ellison looks at today’s carbon offset market. The upshot: offsets are helpful (though there are skeptics when it comes to forestry offsets), but you may not be getting what you pay for.
I returned to Stanford’s Schneider to ask what kinds of offsets he might buy. “It’s legitimate to put windmills in if you displace fossil-fuel power,” he said. “It’s legitimate to put coal emissions underground if you could figure out how to make that permanent. Financing a gas plant in India if they were going to put in coal would also be good.” The key with all of these is they reduce carbon emissions at their source.
No one is neutral
Andrew C. Revkin explains why I feel uneasy about the current carbon-offset market:
As long as the use of fossil fuels keeps climbing—which is happening relentlessly around the world—the emission of greenhouse gases will keep rising. The average American, by several estimates, generates more than 20 tons of carbon dioxide or related gases a year; the average resident of the planet about 4.5 tons.
At this rate, environmentalists say, buying someone else’s squelched emissions is all but insignificant.
The worst of the carbon-offset programs resemble the Catholic Church’s sale of indulgences back before the Reformation,” said Denis Hayes, the president of the Bullitt Foundation, an environmental grant-making group. “Instead of reducing their carbon footprints, people take private jets and stretch limos, and then think they can buy an indulgence to forgive their sins.”
“This whole game is badly in need of a modern Martin Luther,” Mr. Hayes added.
