Like my friend Henry, I’m overweight and trying not to be. He is, I think, a couple of “stone” heavier than I am. (Whatever the hell that means – you’d think that dealing in pounds and kilograms alone would be confusing enough for the British, but apparently there’s no such thing as excessive conversion confusion in the UK. But I digress.) Anyway, I’m currently 40 or so pounds past where I should be.
My personal weight loss “plan” (for lack of a better word) is not very diet-focused at the moment. I’m losing weight right now through the simple process of burning more calories than I consume. In other words, I’ve actually been exercising.
As some of you are probably aware, there comes a time during a good workout when death begins to feel less like a possibility and more like a desirable outcome. Whenever I reach that point, my thoughts tend to get just a little bit whimsical. I hit that point a couple of hours ago, when I was at about the 90% mark in my bike ride. As my legs began to remind me that a quarter-degree upgrade might not seem like much, it gets real old after a mile or so, my mind desperately tried to move me on to other topics. In this case, I started to wonder just how much carbon dioxide my weight loss plan was adding to the atmosphere, and how much of a favor overweight Americans really might be doing for everyone.
Let me explain.
When we think about things that lock up carbon dioxide, we usually think green – as in trees, and plants, and other types of vegetation. But we’re all carbon dioxide sinks, at least for the duration of our lives. We eat plants, and things that eat plants, and turn what we eat into us. All of the carbon in your body – and there’s lots of carbon in your body – was carbon dioxide in the atmosphere not all that long ago.
When we lose weight, our bodies use our mass to make energy and some byproducts, including carbon dioxide. We exhale the carbon dioxide, it goes back into the atmosphere, and back into the global carbon cycle. If we stay fat, there’s less carbon dioxide in the atmosphere. Eat more, help the planet. Sounds good to me.
Before we all go out and stage a run on McDonalds, it might be worth checking with reality.
I’m about 18 kg overweight, and the human body is about 23% carbon by weight. That means that my excess weight is currently storing all of about 4 kg (less than 10 pounds) of carbon. Even if every single American was as overweight as I am, and all 300 million of us lost all the weight this year, that would add a bit less than 1.5 megatons of carbon to the atmosphere. We release about 8 gigatons of carbon into the atmosphere annually. That means that if every American lost all their excess weight this year, it would actually add much less than 0.1% to the total carbon output.
So, no, you’re not going to hurt the environment if you lose weight. Sorry.
Believe it or not, though, there was actually a reason I brought this up. Individually, each of us contains a negligible amount of excess carbon. Collectively, the pounds add up – one tenth of one percent of the annual carbon output might not be much on the global scale, but it’s still nothing to sneeze at. Something that’s individually miniscule, when multiplied over huge masses of people, can produce enormous effects.
Which brings us to the light bulbs. As you might know, we’re phasing out most incandescent lightbulbs over the next few years. They’ll be replaced with the compact fluorescent bulbs that many of you already use. Individually, each bulb uses a tiny amount of electricity, but together they really do add up.
Let’s assume, just for the sake of calculations, that the average American household burns the equivalent of 6 100-watt incandescent bulbs for five hours every day. That’s a guess, but I think it’s more likely to be low than high. If those bulbs are converted to fluorescents, they’ll use about 25% of the power, but produce the same light. That’s a difference of about 450 watts per hour. Over the course of the year, switching over will save about 820 kWhr.
The amount of carbon dioxide produced per kilowatt hour of electricity produced varies quite a bit, depending on the fuel burned. Based on the sources for US power, it looks like 0.6 kg/C/kWhr is a reasonable estimate. Using that, each American household to switch will add about half a ton less carbon to the atmosphere than they would have using incandescent bulbs. That’s not that much.
But there are about 110 million American households. Phasing out incandescent bulbs forces all of them to switch. That’s a savings of about 55 million tons of carbon annually. We’re currently emitting about 1.7 gigatons annually, so, assuming I haven’t borked up the maths somewhere, that’s about a 3% annual reduction in our emissions.
If enough people make little changes, big changes really can happen.