The Climate in Emergency

A weekly blog on science, news, and ideas related to climate change


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The Carbon Footprint of a Beagle

So, we just got a beagle.

We already had one beagle, but after the death of her co-dog (a Lab/pit mix) last month, she’s been lonely, so we got her a companion. His name is Reilly, and he is sweet and affectionate and already causing trouble in his distinctively charming and beaglish way.

This seems like a good time to cover a topic I’ve been interested in for a while, the relationship between climate change and pets

The Carbon Footprint of Pets

Turns out, there have been serious scientific studies of the carbon footprint of dogs and cats. Results vary, but the general consensus tends to be that pets, collectively, have a large carbon footprint because there are a lot of them and dogs and cats eat mostly meat, which is a carbon-intensive food.

There are a couple of interesting points, here.

First, these studies may be studies of the carbon footprint of pet food, not pets. One research team is quoted as having looked at dog food only, based on the assumption that other aspects of dog care have minimal impact. Their assumption may be correct, but personally I’d like to see a study that examined all aspects of dog (and cat) care so we could check the accuracy of that assumption. I’m also amused by their conclusion, that big dogs have a larger carbon footprint than small dogs, since big dogs eat more. Personally, I’m not sure why anyone would assume the non-food aspects of dog care have minimal impact (a complicated question involving lots of data most of us don’t have) but then perform and publish a formal study on whether big dogs eat more than small dogs do.

Second, sorting out the carbon footprint of food may be trickier than it appears. For example, pet food is often made, in part, from meat by-products, which humans can’t eat. By-products are essentially waste for which a market has been created, stuff that would not exist if the primary product (muscle meat for human consumption) were not being produced. So is it really fair to assign the carbon footprint of the meat by-product to the dog who eats it rather than to the human whose demand for steaks created that steer in the first place?

The carbon footprint of food can vary a lot, as we know from studies of human diets. For example, beef and lamb are much more carbon-intensive than chicken. I’d like to see a detailed break-down of several different kinds of pet food and the different aspects of their production.

To Pet or Not to Pet

What does the question “what is the carbon footprint of a pet?” really mean? We could ask about the carbon footprint of Reilly and what we, his guardians, can do to make him a “greener” dog. Alternatively, we could be asking about our own carbon footprint and whether not having Reilly would make my husband and I “greener” people.

And since Reilly’s personal impact on the climate would presumably be about the same no matter who had him, the latter question really boils down to the draconian “should Reilly be alive?”

In a similar spirit we might debate, or refuse to debate, the lives of human children. Indeed, since humans have huge carbon footprints, especially in the so-called “developed” world, some list “having a child” as the worst thing a person can do to the planet, even worse than airplane travel, car travel, or eating meat.

My husband and I don’t have children, and environmental impact is part of the reason, but phrasing the decision as a measurable reduction of our carbon footprint as a couple seems very wrong.

What if the child in question were the next generation’s Rachel Carson?

The very idea of reducing a child to a carbon footprint is offensive. Reducing Reilly in such a way is less so, but still pretty bad.

But Haven’t There Always Been Dogs?

There is an argument to be made for having fewer dogs and cats in total. Their collective environmental impact is not negligible, and most humans could get along without them quite well (I said most, not all). But if all dogs and cats suddenly vanished, would the carbon footprint of humanity really shrink? Or would some other use be found for meat by-products?

Perhaps more to the point, would climate change really slow?

This whole line of questioning reminds me of cows. There is an argument to be made for having fewer head of cattle, too, after all, since their environmental impact is quite large, and we can eat other things. But when I brought up such an argument a while back, a friend of mine posed an interesting question; haven’t there always been cows?

And yes, cows are not new. I’m fairly sure there are a lot more now than there used to be, but surely before the modern mountain of moo there were other ungulates, bison and caribou, antelopes and takhi and quagga, to take up the slack.

Ok, those last two aren’t exactly ruminants, but you get the point. The only way large herds of cattle could actually change the climate would be if the total number of ruminants, domestic or otherwise, had grown–and how would such increased stock find enough to eat if something else hadn’t changed?

The same question applies to dogs and cats. If these animals have not simply replaced their wild counterparts but actually exist now in excess of the total historical animal mass, where did the excess food come from and why isn’t it accounted for in the historical carbon balance, where the carbon each animal releases came ultimately from plants and returned to plants again for no net change?

Some other source of energy must be fueling the swelling populations, something from outside the old balance–fossil, presumably, in one way or another. In other words, if the total population of dogs (or cattle or humans) has grown too large for the planet, it is a symptom, not a cause, of our problem.

As useful as carbon footprint calculation can be, it’s possible to get lost in the weeds here and miss the larger picture, which is that the climate is changing because the concentration of greenhouse gasses is rising, period.

Reilly can’t introduce additional carbon to the system. He just can’t. If he is alive because of such an introduction, his death at some shelter would not begin to solve the problem.

Take Home Messages

Yes, certainly it makes sense to feed pets the most climate-friendly diet possible. And people who are bound and determined to buy a pet from a breeder might seriously consider a little vegetarian, like a rabbit, instead of a big carnivore, like a retriever–shift the market in a more climate-friendly direction.

But you are not going to fight climate change by not getting that beagle from the shelter.

Let’s keep our collective eye on the ball, the ball being to get off fossil fuel completely as soon as possible. Only then can we fix the problem that causes all the other problems.

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Solar Impulses

This past week, I saw a documentary on the flight of the Solar Impulse 2, the first airplane to circumnavigate the globe without fuel–the plane is solar powered. It’s a great story.

The visionary behind the project, Bertrand Piccard, is the latest in a long line of brilliant dare-devil explorers who have been building and piloting record-breaking balloons and submarines and the like for generations. His great-uncle, Jean Felix Piccard, was the historical inspiration for that Star Trek captain with a very similar name, and the real and fictional Piccards actually bear a bizarre physical resemblance; Bertrand looks like a relative of Jean-Luc. The airplane itself is one of those objects everybody insisted could never be built, could never work–to have enough solar cells to generate enough power, the plane would have to be very big, but big planes need even more power to fly, so the plane would have to be even bigger, which would mean…unless the plane were absurdly light and under-powered (and still big), in which case it would be hard to fly and prone to break if a cloud looked at it funny. Impossible. But Captain Piccard assembled a team, said “make it so,” and they did, and it worked, and there you go.

Just to give everyone due credit, the plane had two pilots who took turns, Mr. Piccard and Andre Borschberg, and a large team of engineers and other mission-support personnel, without whom the project would not have worked.

Obviously, part of the motivation for the whole project was the coolness factor. Mountaineers climb Everest “because it’s there,” and Piccards probably invent and pilot unusual flying machines or submarines for similar reasons. But the specific mission for the Solar Impulse 2, and the thing that brings it under the purview of this blog, was to raise awareness for renewable energy. While the plane itself is far from practical (it can only carry a single person–the pilot–and only under ideal conditions), its existence suggests greater things to come and, as Mr. Piccard is fond of pointing out, everything is more difficult in the sky, so if solar power can work even marginally for an airplane, there’s no excuse for not using it on the ground.

All of this is laudable. There is a long history of impractical-seeming exploration leading to very practical technical innovation, and there is much to be said for crazy stunts as a way to get media attention. If flying around the world in an extremely fragile experimental airplane gets you on TV saying “climate change is real and important and we have to do something!” than I am all for it. These people are doing it right, making a difference.

Also, based on his appearance on the documentary, I find Bertand Piccard impossible not to like. He positively glows with a kind of driven, excitement, the kind of delighted passion usually called “childlike,” except it’s also obvious that you’d better not get in his way. He’s probably hard to live with, but as I don’t have to live with him, I’m free to just think he’s really cool. And he’s good-looking, so that helps.

I point all this out in order to make sure my next question is not misunderstood:

What was the carbon footprint of this project?

I suspect somebody has calculated the answer, but finding the number is not really the point–I’m sure the footprint was huge. Consider just two aspects of the project. First, the plane took off from Abu Dhabi, and eventually returned there, triumphant, but that’s not where it was built. The documentary clearly showed the Solar Impulse 2 arriving at the Abu Dhabi airport inside the belly of a giant cargo plane. That cargo plane was not solar powered. Second, the Solar Impulse 2 can carry only one human at a time, but it had two pilots who alternated. One pilot would land and, I assume, go sleep in a hotel for three days, and the next pilot would board and take off. That means that the relief pilot, not to mention the ground crew and the specialized portable hanger, must have flown (in non-solar aircraft) to the meeting place. Since weeks or months sometimes went by between the legs of the journey, the pilots probably flew home sometimes, too.

It’s not that the project was necessarily carbon-heavy as such things go, but it obviously wasn’t carbon-light, either, and it definitely wasn’t a flight around the world using no fuel. The airplane that doesn’t use fuel requires the support of those that do.

As I said, the value of the project was as an early proof of concept and as a stunt designed to trigger necessary conversations. As such, it was a good and important project. But I’d like to suggest a follow-up:

How about a team of people go around the world ACTUALLY with zero fossil fuel?

Or, better yet, several teams, and have them race? They’ll be walking, biking, sailing, rafting, and in some areas using plug-in hybrid cars and possibly some experimental technology. The race will provide both audience interest and an incentive for teams to innovate, rather than simply walking and sailing for three or four years. Infrastructure and technology will be tested and explored, possibly triggering useful innovations, such as bike lanes and walkable city designs. Local people will appear in interviews on BBC and PBS with translators doing voice-overs. It will be great.

Because we know that climate change isn’t really a technological problem. Better technology will help, but we could do a lot more to combat climate change with the technology we have. The problem is cultural and political, and requires cultural and political solutions.

A big, attention-grabbing demonstration of the zero-carbon transportation tools we already have might help.


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Oh, Christmas Tree!

The other day, my mother asked me whether she ought to switch to artificial an Christmas tree, for environmental reasons. This question has been addressed by other authors (please check those links for my source information), and the short answer is “no.”

(Don’t you like straightforward answers, Mom?)

But why the answer is no is interesting, as are the exceptions–my husband and I use an artificial tree, for example.

Natural Christmas Trees

You’d think this would start with a side-by-side comparison of pros and cons of each option. After all, using a natural tree involves cutting down a tree, and that can’t be good, right? But while I admit that cutting is bad for the individual tree, that’s not how conservation works. The health of the land as a whole doesn’t depend on the longevity of individual trees, but on the functioning of a whole system. While it’s possible to imagine Christmas trees being cut in environmentally destructive circumstances, I’ve never actually heard of the Christmas tree trade being a major driver of deforestation. Instead, Christmas trees are generally grown on farms–and a Christmas tree farm is a much better bet, environmentally speaking, than, say, a housing development. The growing trees do provide some wildlife habitat, protect and develop soil, and sequester carbon.

Most of the carbon sequestered by a growing tree is, of course, released when the tree dies and the wood rots or burns, but the farm as a whole holds carbon as generations of Christmas trees grow there. And while transporting the cut tree does involve carbon emissions, but depending on how far the trees have to travel and what happens to them after Christmas, these emissions can be minimal. Typically, half of a tree’s total carbon footprint comes from the trip the family makes to bring it home. If you drive less than ten miles to get the tree, and especially if the tree is mulched afterwards, rather than landfilled, your Christmas tree can actually be carbon-negative–that it, it fights global warming, rather than adding to it.

Even if you do drive farther for your tree, its carbon footprint is still dramatically smaller than that of an artificial tree.

Artificial Trees

It might be possible to produce sustainable artificial Christmas trees, but that’s not what is available in the stores. Artificial trees are almost always made of a combination of PVC plastic and steel, which are both carbon-intensive materials. They are recyclable, but virtually no recycling centers are prepared to disentangle the two, so artificial trees are typically treated as trash. The trees are also almost all made in China, meaning that they travel much farther (at a much greater carbon cost) than real trees normally do.

It is true that real trees are used only once and artificial trees can be used over and over–but if the live tree you’re comparing it to was carbon-negative, that’s irrelevant. The real tree is always going to be better. As for comparisons with live trees that do have carbon costs, estimates vary from five to 20 years, as to how many years an artificial tree must be used before its annual carbon cost starts to equal that of the real tree.

Most people replace their artificial trees after only six years.

Exceptional Trees

Whether artificial or real trees are better in the abstract is one question. “Which tree should I use?” is a completely different question. For example, our artificial tree is second-hand, and it likely would have been thrown away had we not taken it. Arguably, the environmental cost of the tree belongs at the feet of its original owners, since their decision not only paid for its manufacture, but also made certain it would one day need to be disposed of. We got the tree for free, environmentally speaking, and it saved us from having to buy any tree of any kind for well over ten years, now (my husband doesn’t remember when he got it, but it was here when I arrived).

You could also make your own artificial tree out of sustainably-sourced materials. You could also decorate a houseplant as your Christmas tree–balled and burlapped trees usually die, and spruces grown in pots as Christmas trees are only slightly more likely to make it, but you could decorate a Norfolk pine or another species that does well as a houseplant. You can do a little research to determine whether locally-grown trees are available in your area, whether Christmas trees can be mulched in your area (if you have a yard, you can also set your post-Christmas tree outside to provide cover for wild birds) and, if you want a live tree, you can make sure to pick it up from someplace less than ten miles from home (depending on the gas mileage of your vehicle).

In short, which tree you should use (assuming you want one at all) depends, in part, on your situation.


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The Carbon Footprint of a Book

So, I’ve got a book coming out.

Technically, this is a second edition. Last summer, I published my first novel, To Give a Rose, but a few months later my publisher had to drop the project for reasons that had nothing to do with me. After much difficulty and confusion, I have finally found a way to get my book back into print; it’s due out next month.

Of course, this will make me responsible for a huge weight of paper product when (hopefully!) I sell lots of copies. Of course I’m concerned about the environmental impact of all of this, so I set out to do some research, beginning with the search term “carbon footprint of a book.” What I found was interesting and somewhat contradictory and uncertain.

How Carbon Footprinting Works

The problem is that carbon footprinting anything is complex and uncertain. In theory, to find the carbon footprint of an object, you look at how it’s made, how it’s transported, how it functions, and what happens to it when it’s disposed of, add up all the sources of greenhouse gasses in all these processes, and there you go. The figure is usually expressed as pounds (or kilograms, or tons, or tonnes) of carbon dioxide equivalent–different greenhouse gasses have different warming potentials, so for simplicity we use the warming potential of carbon dioxide as a kind of standard.

The problem is that in practice literally adding up all associated greenhouse gas emissions is usually impossible. Our economy is so complex, and manufacturing chains are so long, that a single product–in this case, a book–might involve resources sourced in dozens of countries and handled in multiple factories in a dozen different countries. That’s hundreds or even thousands of steps, each of which could have its own separate greenhouse gas emissions.Totally unworkable.

Carbon footprinting depends on imagining a simplified version of whatever manufacturing process you’re looking at, one that has a carbon footprint approximately the same size as the real one. But this simplification process is always a judgment call, and different analyses of the same product can yield very different results.

There are two other sources of complication.

One is that similar products might be products of very different manufacturing processes. A book printed in the United States using paper made from American trees might have a different footprint than one printed in the UK on paper made from European trees because of differences in the forestry practices and energy grids of each country.

The other complication is that it can be hard to determine what belongs in a given object’s footprint and what does not. For example, the footprint of a book should clearly include emissions associated with felling and milling the tree used to make the paper, but should it also include the lost carbon sequestration potential of that tree? What about the car the logger used to get to the job site to fell the tree? What about the Freon in the air conditioner of that car, if the logger used the air conditioner on the way to work? And so on. Clearly one has to draw a line somewhere, but where? A particularly vexing version of this problem comes up with recycled paper. Obviously, processing the same fibers twice uses more energy than processing them only once, so recycled paper ought to have a higher carbon footprint than non-recycled paper–unless you consider that the carbon footprint of the initial processing belongs to the first, “virgin” generation of paper only, in which case the recycled paper’s footprint might be much lower.

Again, judgment calls abound and can differ.

All things considered, carbon footprinting is only a rough tool useful for estimation. Its best application is probably for comparison of several alternatives all analyzed according to the same set of judgment calls–for example, a comparison among different protein sources or different types of energy generation. The technique does not yield definitive figures. An object cannot have a known carbon footprint the same way it can have a known weight or size or calorie count.

Carbon Footprints of Books

A Canadian paperback

I was able to find several different versions of carbon footprint assessments of books. The most extensive was probably one published in the Journal of Industrial Ecology, which presented the footprint of a paperback book printed in Canada on American paper. Unfortunately, that journal does not make itself available for free and I don’t have money. I was only able to read the Abstract (summary), which is available for free but does not have as much detail as I’d like.

The study came up with the figure of 2.71 kilograms CO equivalent (CO2-eq) per book, based on a production run of 400,000 books mostly distributed in North America. That figure applied only to the book through its production up to sale. The study also looked at three different end-of-life scenarios for these books (how long they last, how they are finally disposed of, etc.), but unfortunately the Abstract didn’t describe those scenarios or list their results.

One curious result of the study was that post-consumer recycled paper had a much higher footprint than virgin fiber. As noted earlier, that could be due, in part, to debatable judgment calls in the analysis method, which the Abstract did not fully describe. However, the non-recycled paper they analyzed came from a mill that used wood residue and other byproducts to generate power, thus substantially reducing reliance on fossil fuel and yielding paper with a lower footprint. Presumably, a recycled paper plant would not have access to such residue and is therefore much more likely to depend entirely on fossil fuel.

A Finnish hardback

This analysis comes from a brochure on the environmental impact of Finnish book production. The brochure describes its methods in detail and is both easy to read and thorough. To read it yourself, click here.

Among many other interesting facts, the brochure asserts that a single book has a carbon dioxide equivalent of 1.2 kilograms. Again, that leaves out the impact of the book’s disposal. Does a Finnish hardback really have less than half the carbon footprint of a Canadian paperback? We can’t really say, because the two studies are not directly comparable, but it is possible–especially if Finland has a less carbon-intensive power grid than Canada does.

The brochure further states that the vast majority of a printed book’s footprint is in the production of its paper and in the printing process–fiber supply and transportation contribute relatively little (at least in Finland).

An American book

I also found a reference to an analysis of the American printing industry that gave roughly 4 kg CO2-eq per book and listed the use of virgin paper as far and away the highest contribution to the footprint–in apparent direct contradiction to the other two analyses. Probably the discrepancy is again due, at least in part, to details of how the analyses were completed.

What About eBooks?

eReaders

What about books that don’t require paper? eReaders themselves have a carbon footprint associated with manufacture, transport, and disposal. These devices also have other environmental impacts associated with the production of metals, heavy metals, and plastics which are important but are outside the scope of the article. According to at least one study, the carbon footprint of the ereader alone is cancelled out after a few years because of all the paper books it replaces.

Curiously, the number of paper books replaced could be much higher than it might at first appear, since they don’t just replace the printed books that people read but also the printed books that people don’t read. Roughly a third of all the books that arrive at a book store are never sold. These go back to the publisher and are either pulped and recycled or added to the waste stream. Presumably, some percentage of books are actually thrown out soon after purchase as well. Incinerating or landfilling paper releases its carbon, meaning that the carbon footprint of a book in the trash is higher than that of a book in a library. If each printed book in a personal collection has a shadow-footprint of sibling-books that never made it, then switching to ebooks could carry substantial carbon savings.

That’s assuming that more ebooks actually mean fewer printed books and fewer printed books wasted, something that is not necessarily true.

Books online

But there is a book difference between a book on a machine and a book on a shelf–once a book is printed and shipped, it causes no further emissions until its eventual demise. If the book lasts as long as the tree would have, which is quite possible, its eventual yielding of its carbon could be no different than the eventual rotting of an old tree. In any case, the longer the book lasts and the more people read it, the lower the carbon footprint of reading it gets. With an ebook, reading it requires electricity every single time–and for books stored in the cloud, electricity must be constantly in use to keep those books available on servers. I am unclear whether that continued electricity usage has been included in the calculation of the footprint of ebooks.

The internet uses a fantastic amount of energy, though exactly how much seems debatable. That’s the bad news. The good news is that companies with a large online presence can use their economic muscle to build renewable energy capacity and some have done so. eBooks could therefore be a potential driver of conversion away from fossil fuel use, if the industry chooses to put its weight in that direction.

Bringing It All Together

If indeed most of a book’s footprint is due to paper manufacturing and printing, if that figure is not unique to Finland, that suggests that whether a book is printed on recycled paper is actually a lesser consideration. The real bang for the buck, as far as shrinking footprints are concerned, lies in making paper manufacturing and printing more efficient and less carbon-intensive.

In both cases, the mechanical efficiency of the plants themselves could probably be improved, but I really don’t know. The big deal is almost certainly the power grid; the carbon footprint of a book depends largely on the emissions of the power grid its production is plugged into. Since the power grid also determines much of the emissions related to ebooks, shrinking the carbon footprint of a book is really about transitioning the power grid off of fossil fuels–and paper mills, printing companies, and internet servers can all help drive the transition by demanding capacity that other users can then tap into.

So, What Does this Mean for Writers and Readers?

Arguably, the carbon footprint of a book belongs to its reader–personal carbon footprinting assumes personal responsibility for anything we buy. Since the same footprint can’t belong to two people, that would mean authors don’t bear the weight of the carbon emissions of their books–but that way lies paralysis. A reader seldom has an opportunity to choose low-carbon books over high-carbon copies, and in any case, reading materials are seldom a significant part of household footprints. Readers are unlikely to drive any sort of change, here. Writers have a little more power.

Writers can ask their publishers to take certain steps towards “greening” their processes. The publisher may or may not say yes–we live in an era when writers who are not J.K. Rowling or Stephen King have very little power–but we do have options and can explore them. I have already asked the printer I’m using now to use a paper with a higher post-consumer recycled content when possible and they said yes. This was before I found out that recycled paper might have a higher carbon footprint, but I’ll stick with it, since it sounds like virgin paper is only lighter on carbon because its production has access to alternative power generation. That implies that recycled paper could be just as climate-friendly if the mill that produces it buys renewable power. I therefore intend to ask whether we can get paper from a company that does so.

Climate-friendly paper might not be available, but it’s worth asking. If enough people ask, it might become available.