Eat local, seasonal and low on the food chain to minimize climate chaos gas emissions
According to a UN study reported in the Guardian, climate change emissions from shipping amount to 1.12 billion tonnes of CO2 a year, or nearly 4.5% of all global emissions of the main greenhouse gas. This is almost three times higher than previously believed. Ships exploit a ready supply of the world’s cheapest, most polluting “bunker” fuel. Marine heavy fuel oil, which is burned by all large ships, is the residue of the world’s oil refineries. It is as thick as tar. Burning the stuff also releases alarming levels of cancer-causing air pollution (see pdf graphic). The industry has grown rapidly – to the point where it now carries more than 90% of the world’s trade by volume, and has tripled its tonnage carried since 1970. Cargoes also have to travel further due to a shift of production away from the US and Europe to China and south Asia.
“Food imports from China have exploded over the past decade, rising nearly 300% to more than $705 million last year,” says a May article in the Toronto Star that cites Statistics Canada. China is now Canada’s fifth largest supplier of fresh fruits and vegetables. Another big category is fish and seafood. At the Toronto Food Terminal, Chinese peas sell for ten dollars a case. A vegetable wholesaler told the Star, “In Canada you couldn’t do it for that price if everybody worked for free!” There is the risk of Canadian farmers being priced out of existence.
On a positive note, sea-freight emissions are much less than if you were to ship the same weight by airplane. The aviation industry is responsible for about 650 million tonnes of CO2 emissions a year. And due to their huge cargoes, ships are usually more efficient than trucks, and you don’t have to build highways.
Local foods not always best
The New Yorker has an eight page article titled Big Foot that takes a close look at carbon footprints. The local 100-mile diet – eating only foods produced within a 100 mile radius – has been promoted as the ultimate in ecological eating. But it turn out that when evaluating food, you have to consider the entire life cycle of the product. For example:
- Importing New Zealand apples and other foods may result in less carbon emissions because the country receives plenty of sunshine and gets most of its power from dams.
- “Importing beans from Uganda or Kenya – where the farms are small, tractor use is limited, and the fertilizer is almost always manure – tends to be more efficient than growing beans in Europe, with its reliance on energy-dependent irrigation systems.”
- Greenhouse-grown roses in Holland require six times more energy than roses flown from North Africa to Europe.
- Because of methane emissions and feed crops, local meat has a much higher climate change footprint than imported vegetarian alternatives (more on this below).
I buy imported avocados, limes, rice and lentils. But learning about the environmental costs of shipping reminds me to keep the focus on locally-grown and seasonal foods. Seasonal means eating stuff when it is in season (such as strawberries in June), or hearty foods such as roots, cabbage, squash and apples that have had their season extended by proper storing. Dry foods like grains, legumes, nuts and seeds are effectively always in season because they easily store for months and months. Preserving local food by freezing, drying or canning is another solution.