Monday, October 13, 2014

Book Review: Diet for a Hot Planet

Last week I finished up reading Diet for a Hot Planet, and boy did I learn a LOT. It's a book I'd recommend to anyone interested in climate change, because the production and distribution of our food is responsible for 31% or more of global warming effects world-wide. But as someone who's been a locavore for several years now, it was a book of special interest.

I became a locavore originally to reduce the fuels used up in transportation of my foods. It's been suggested to me in the past that this is misguided at best. This book backs me up to a certain extent, but also shows that distance travelled is really only part of the emissions equation. One London study found that production accounted for about half of the emissions related to the foods studied; transportation produced about one fifth.

Before I delve into some of Ms. LappĂ©'s information, let me point out that everything I'm about to write here applies to whole foods. I’m not talking about the evils of packaging, or junk food or fast food. To consider the impact of these issues, you'd need to add a whole other layer of bad, bad, bad.

As a matter of fact, I'm not even going to start with meat. Let's talk about conventionally farmed vegetables and fruits. The best-known difference between conventional and organic produce is the use of pesticides and fertilizers. What you may not know is that, while both are made from petroleum, they also use a large quantity of energy – in the form of fossil fuels – in production. In the U.S. it's made using natural gas; in China, coal.

I think most of us also know that soil is poorer with the use of chemical fertilizers and pesticides. Healthy soil serves as a carbon sink, absorbing carbon and storing it. In unhealthy soil, stored carbon is released as carbon dioxide.

Additionally, chemical fertilizers break down and release nitrous oxide, a greenhouse gas with the potential to produce 296 times the global warming as the same amount of carbon dioxide. Nitrous oxide is the third-most significant greenhouse gas (measured in carbon dioxide equivalence). At 7.9% of all total emissions (again, by equivalence), it's not the biggest piece of the pie by a long shot – but it's still an important part of the puzzle.

Next, transportation. This is where a locavore focuses their energy. As mentioned earlier, it's likely that this is an important consideration in choosing "cool foods," but it's not the biggest. As always when considering food miles, you'll want to look at all the layers inherent in production – as the author puts it, "the food's inputs – not just the distance from the field to the plate." Fertilizer from far-flung parts of the world, feed for the animals that produced your meat and dairy products. And if it's a processed food, multiply that by each ingredient.

It's also worth noting that food is probably travelling further than you knew. In some places you will see an "average figure" of 1,500 miles that food travels – but that's related to one very limited study of a selection of foods travelling within the United States to the Chicago Terminal Market only. Ms. LappĂ©'s best guess is that "the average food miles for typical food consumed in the United States is most likely significantly higher." (Emphasis hers.) In fact, a California study she cites elsewhere in the book found that emissions were 45 times greater for imports than for local, and up to five hundred times greater if travelling by air freight.

Finally, we can cover livestock. Livestock production in its current form creates a staggering 18 percent of greenhouse gas emissions globally. As a locavore I've eaten a lot of grass-fed beef and local milk, but the truth is, ruminants produce loads of methane no matter how they are raised. Methane is the second-most significant greenhouse gas, 23 times as powerful as carbon dioxide but mercifully less prevalent. It's the same "natural gas" that energy companies are drilling into shale for, which is why I once joked that we should raise cows to produce methane instead of milk – by volume, they certainly make more of the gas! It's almost 10:1.

If you're eating conventional meat, though, you've got more than ruminant burps to worry about. The same layering effect mentioned above applies to your meat, and it's a real doozy. Globally, half of all corn and 90% of all soy harvested is fed to animals. Two-thirds of all the agricultural land in production is used for raising meat. Half of all energy use related to agriculture goes to raising animal feed. It takes 16 pounds of soy and corn to raise one pound of feed-lot beef. (Please note that soy and corn, unlike grass, could be eaten by people directly, and much more efficiently.) Most of that corn and soy is raised conventionally, with all the related fertilizer, tilling, etc.     

Another issue with conventional meat is the waste. Animals in Confined Animal Feeding Operations (CAFOs) produce so much waste in so little space that in many cases it is stored in what is euphemistically termed "lagoons." Setting aside the risk of weather-related overflow (ew), manure lagoons release methane and carbon dioxide directly into the atmosphere, and not a lot of the stuff gets used as fertilizer or in any other productive function.

Alarming as a lot of this information is, I experience it as empowering. It’s information that I can use moving forward to make more-knowledgeable choices when I set the table for dinner. I've learned so much from reading this book, and truthfully, I expect that I may read it multiple times.

You should definitely pick it up to at least leaf through. Happy eating!