A recent report from the Carbon Trust notes that there are "more carbon emissions from crisps (potato chips) than cement." Although it may be a surprising bit of news at first, it conceals the greater issue of scale. Undoubtedly though, someone is certain to rail against potato chips and argue that we don't need to worry about cement production when snack foods are the bigger problem. While the Carbon Trust's statement is factually correct from one perspective, as the famous saying goes, there are "Lies, damned lies, and statistics", so let's talk about numbers a bit.
First, let's take a look at the amount of CO2 produced for each item. Producing cement releases about an equivalent amount of CO2 (producing one ton of cement releases one ton of CO2), while producing potato chips releases about 2.3 times as much CO2 (producing one ton of potato chips releases 2.3 tons of CO2). What is key here is that the factor of CO2 produced is in relationship to the weight of the finished product. Cement is much denser and heavier than potato chips, so a sack of cement has a much, much higher carbon footprint than an equivalent volume of potato chips.
Secondly, let's consider the annual production of each item. A figure for yearly global production of potato chips wasn't readily available, but just looking at relatively recent US consumption, roughly 3 million tons of potato chips are produced annually, yielding about 7 million tons of CO2. However, US cement production is around 100 million tons per year, yeilding about 100 million tons of CO2.
Even though cement produces less CO2 per pound, cement production is still nearly 15 times more significant to US production of CO2. Although there is more CO2 per unit of potato chips, a lot more cement is produced, which helps make that the larger problem.
However, there's more to it than just that. Global cement production in 2000 was 1.56 billion tons. The US production is only about 6% of that total. On the other hand, the US is probably responsible for a higher percentage of total potato chip consumption, so the global figure for cement production is even more significant.
Big numbers and surprising ratios can catch our attention, but it's important to look at the overall picture. Although more CO2 per pound was released when the potato chips were made, a one pound bag of potato chips still represents less impact than an 80 pound sack of cement; the bags are far from equivalent to one another. And even though producing a pound of chips releases more CO2 than producing a pound of cement does, that doesn't make potato chips a greater environmental hazard than cement.
written by Joshua Mitchell, April 10, 2010
written by Louise Denny, April 12, 2010
written by Knuckle Boom, April 13, 2010
written by hydrophilia, April 20, 2010
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