This week, the Lantern takes a break from answering your green lifestyle questions to report on three studies that raise brand-new environmental dilemmas.
Is meat less of a climate-change culprit than we thought?
One of the Lantern's frequent tips is to cut back on your meat intake for the sake of the planet. But according to Frank Mitloehner, a researcher from the University of California-Davis, that advice is hogwash.
Mitloehner takes exception to the widely cited claim that livestock are responsible for 18 percent of the world's anthropogenicgreenhouse gas emissions—more than the entire transportation sector. That assertion come from a 2006 paper from the U.N.'s Food and Agricultural Organization and has been cited by everyone from Paul McCartney to Rajendra Pachauri, the head of the IPCC (not to mention the Lantern herself), as a reason to reduce our consumption of animal products.
Mitloehner is skeptical about that 18 percent figure but doesn't claim that it's wrong, per se. It just doesn't apply to the United States: According to the EPA's inventory, transportation accounts for 26 percent of America's greenhouse gas emissions, whereas livestock's share is a measly 2.8 percent. Therefore, he concludes, Americans cutting back on meat and dairy would bring relatively small benefits.
But given what a big pie we're talking about, even a tiny slice is pretty substantial: 2.8 percent equals 198 million metric tons of carbon-dioxide equivalent—or roughly all of Venezuela's energy-related CO2 emissions in 2008. Other commenters have pointed out that American livestock are actually responsible for more than 198 million metric tons of CO2-equivalent, since the EPA's figure includes only direct emissions from the animals (i.e., from their manure, burps, and farts). Furthermore, climate change is only one of the ways cows, pigs, and chickens affect the planet—land and water pollution are big concerns, too.
So by all means, we should be looking for ways to reduce our use of fossil fuels for electricity, heating, and transportation, as Mitloehner argues. But curbing our meat intake—particularly red meat, which is so much more resource-intensive than nearly all other food products—still seems like sound environmental advice to the Lantern, even if American farm animals aren't quite the global warming bogeymen we previously imagined.
Mitloehner does have a point when he argues that we should drop the "bigger than the transportation sector" meme, pending better research. Though the FAO researchers tallied emissions from every part of the livestock life cycle, the transportation figures they used considered only tailpipe emissions. If they had done a similarly comprehensive analysis that included the production of the gasoline, vehicles, and roads, the world's cars could very well turn out to have a larger carbon footprint than its cows.
The FAO is currently preparing a more detailed analysis of livestock's carbon footprint for the end of the year—a report that should include a comparison of the impacts associated with carnivorous and vegetarian diets, plus a breakdown of the emissions from different animals, farming systems, and regions. When that happens, you can be sure the Lantern will be reading with interest—and reporting back to you.
Are we outsourcing our greenhouse gas emissions?
When we talk about a nation's carbon footprint, we generally mean the emissions produced within its borders—i.e., whatever gets pumped out from its power plants, factories, and so forth. But because goods produced in one country may be used in another, tallying up direct emissions may not be the best way of assigning responsibility for climate change. So two researchers from the Carnegie Institution of Washington, Steven J. Davis and Ken Caldeira, decided to construct an alternate emissions inventory—one that reflected countries' consumption patterns as opposed to just their production practices.
In their study published last month in Proceedings of the National Academy of Sciences, Davis and Caldeirafound that nearly one-quarter of the world's energy-related carbon dioxide emissions—or 6.2 billion metric tons—is actually "traded" between countries, largely in the form of products moving from the developing world to wealthier nations.