Which has a larger impact on climate change – buying a Quebec-grown Kamouraska lamb shoulder or a Mexican field tomato? The answer might surprise you. This week for Climate Justice week on CKUT 90.3FM radio, I explored the carbon footprint of local versus less than local fruits and vegetables vs. meat and dairy.
When considering “food miles”, most consumers assume that local is better, but the carbon footprint of your dinner depends on what you’re eating, rather than “from where it came”. Authors are writing best-selling books about “100-mile” or “250-mile” diets that encompass eating food produced within these radii.
While there are certainly other reasons to buy local – the food may be more nutrient rich, and certainly in the case of the Mexican field tomatoes, fresher and tastier – the amount of fuel used to ship foreign produce to Canada isn’t the largest factor in determining the “green-ness” of the food. Food may travel tens of thousands of miles to reach your plate, but when you look at the energy needed to produce and process food from start to finish – from seed to plate, or from calf to steak – the final trip to the grocery store is only a tiny portion of the total greenhouse gas emissions, according to environmental and civil engineer Scott Matthews, a professor at Carnegie Mellon University in Pittsburg, Penn whom I heard reporting for Harvest Public Media, an American website, blog, and podcast focused on agriculture as it relates to energy and climate change, food safety, biofuels, animal production and welfare, human health, water quality, and local food systems.
Matthews explained that “if you’re someone who cares about the greenhouse gas impact of food, you should be thinking about diet changes, not localization.”
He received funding from an Environmental Protection Agency fellowship and the National Science Foundation to look into the idea of “food miles”, and his research found that transporting food from the farm to the grocery store on average accounts for only 4% of the food’s total emissions. Approximately 83% actually comes from growing it — from tractor fuel, fertilizer, and the trickle down effect of growing grain to feed animals.
“You also have to consider delivery of fertilizer and seeds to the farm and shipping the food to be washed and processed and boxed,” explained Matthews. His study also found that even if you went totally local, and magically got all your food from zero miles away, you’d likely only reduce your contribution to greenhouse gas emissions by about 5%.
So what’s the big culprit in green house emissions from food? Matthews said, “Cows vs. non-cows.” Well, red meat. Matthews explained that if consumers cut just one day a week of red meat out of their diet, it would have the same effect as if that person bought all their food locally for an entire year. One day a week…
In Quebec that’s a hard thing to ask. We are a province of pork, proud of our lamb, mad about sausages and wild game. We have a wide selection of organic, antibiotic-free, free-range, grass-fed meats. They’re delicious, and we’re a province that proudly supports local with cretons, patés, and chops whenever we can. Surely these well-raised animals are better than the cheap ground beef found on supermarket shelves? It turns out, however, that no matter how the animals are raised red meat still has the highest greenhouse gas emissions because of “both ends of the cow,” said Matthews. Manure and burping emit large amounts of methane – a greenhouse gas 25 times more warming than carbon dioxide. There is a difference between grass-fed and grain-fed however. About 1/3rd of emissions come from fuel used on the farm and to grow the corn feed, so if corn (or another grain-based feed) isn’t used, this is significantly reduced. However, a second study from Jude Capper, a professor of dairy sciences at Washington State University explained that grass-fed beef may actually have a higher carbon footprint because the animals live longer since they take longer to fatten up to slaughtering size, so they emit more methane over their lifetimes (and it turns out that eating grass for cows is like eating beans for humans – a little hard on digestion, and gas-creating).
Healthy soil practices may reduce up to 1/3rd of emissions, which could come from more sustainable practices or farm efficiency. So ask the farmer or butcher where you buy your meat if they can tell you a little more about how the animal was raised before you purchase your next T-Bone. They may not be able to tell you if the cow was bathed in champagne, but they may know about what it ate at least.
And, despite the still high footprint of red meat relative to fruits and vegetables, over the last 30 years the cattle industry has improved the growth rate of cattle and the beef yield per animal, effectively saving about 125 days of feed, fertilizers, fuel, and obviously the methane from those animals as well, helping to cut carbon footprints by 18 percent in that time period,” Capper said.
But meat is still a much larger problem for emissions than that Pattypan summer squash. In order highest emission producers to lowest the list goes from red meat with the highest emissions by far, followed by dairy, then cereals and carbs, then fruits and vegetables, then chicken and fish and eggs. So the message isn’t to be a vegetarian, simply to be aware of the emissions of your food choices. But are your free-range chickens better than those kept in cages? In terms of animal welfare, definitely.
So even though eating local makes a relatively small impact on reducing carbon emissions, Matthews said he still buys from neighbourhood markets with local produce. He does it simply to support local agriculture and for freshness. And there are also environmental benefits of eating local including preserving genetic diversity – farmers are growing heirloom varieties of tomatoes and greens – and diversity means a more stable and sustainable food future.
For more information on the carbon emission effects of red meat and the average carbon footprints od many of our imported fruits and vegetables, go to Harvest Public Media and read the article “There’s less to that food mile than you might think.”
I’ll still go to Henry’s Market in Montreal West regularly to get my preservative-free white pattypan squash, greenhouse cherry tomatoes (another difficult to calculate emissions factor), and local garlic. And I’ll still go to the Mile End Farmers Market and occasionally get a lamb sausage to make jambalaya. Henry can tell me where all his vegetables come from including those from a farmer on the other side of the Ontario border whose squash he brought in that morning. And the lamb guy at the Mile End market can wax poetic about his antibiotic-free animals, which is both a comfort and a selling point. Henry doesn’t sell red meat, but that can be a rare treat, knowing that every day I don’t eat any cow, lamb, emu, deer or elk, I can feel slightly less bad about loving mangoes. It’s not a fair trade for the environment, but there are probably greater evils – such as Big Macs, and the Keg Restaurants…