Apparently, they’re pretty good, both in terms of carbon intensity and of course taste. The book, How Bad Are Bananas is pretty good too, although its carbon intensity delivered from Texas A&M through interlibrary loan was a little high. The book quantifies the carbon impact of many common items and services, like the cell phone and the service (the service is more intensive than the device), and is conveniently organized by impact size. If Smoky the Bear’s admonition wasn’t enough, starting a bushfire (165Mt CO2e, Australian bushfires of 2008) (Berners-Lee, 2010, p. 162) is probably the worst thing you could do in greenhouse gas impact (unless you’re plotting a Dr. Strangelove Thermonuclear Apocalypse, >690Mt … but going all out is also likely to precipitate a nuclear winter) (Berners-Lee, 2010, p. 169).
There were some surprises:
- Being a vegetarian is better, but still not really that much lower in carbon intensity than being an omnivore.
Being a vegan, as one would suspect, is much lower in intensity than vegetarian or omnivorous diets. Cheese takes a lot of milk, which takes a lot of feed. Eggs are derivative production (corn+soybeansàchickensàeggs) and there’s a lot of nitrogen released in the dung, which has its own impacts. Follow Michael Pollan’s advice: “eat food, not too much, mostly plants.”
Rice has a disturbingly high impact, because of the flooding of the paddies. Considering the calories per unit land, it’s still a good crop, but rational policy balances the use of land (what can grow here) with carbon intensity and energy density (kcal/hectare).
- Trains aren’t that great, compared to buses.
Trains are heavy. They’re overengineered to provide for a margin of safety well beyond that justified by the probability of accident (which is very very low). Trains are probably the safest way to travel—even without having a crashworthy train (considering the size and weight, it’s pretty hard to build a crashworthy train.
Fortunately, they can be much faster, cutting into the need to travel by plane—so taking the TGV might be lower intensity than taking a flight.
- Natural products aren’t necessarily better.
Leather is pretty intensive because it comes from cows. Leather shoes lose to Crocs. Cotton might grow on plants, but synthetics might be more eco-friendly in terms of carbon intensity, due to washing and drying—and how long the pants will last.
This is all very complex. Carbon isn’t the only metric, of course—toxic impact, human labor use, animal treatment … they all need to be quantified in the decision process. It’s hard to walk away from this book without wondering if you’re a Bad Person or actually not so bad in the scale of things. I suppose I have a relatively large impact, flying too much but not as much as others, being an omnivore, owning (but seldom using) a car (which has long paid off its embodied energy) …
The final takeaway is to not waste your money on carbon offsets—unless the utility is using your contribution to actually build more infrastructure, you’re being taken for a sucker (Berners-Lee, 2010, p. 58)