We hear a lot about a person's carbon footprint, and with the celebration of Earth Day in vogue, maybe we should take a look at what we mean by our carbon footprint.
A carbon footprint is defined as all the greenhouse gas emissions caused by any organization or person, as well as events and products consumed by those two entities. Greenhouse gases can be produced through many avenues, not just fuel emission from transportation, but also any activity that requires fuel. This includes consumption of food and daily living. I addition, as living beings we produce and exhale huge amounts of carbon dioxide each minute while consuming even greater quantities of oxygen. It's interesting to note that microbiology classifies humans as chemo synthetic heterotrophs (or at least that's what I was told back in microbiology class), i.e. we require organic compounds of carbon and nitrogen for nourishment while creating other chemicals as byproducts. It should be noted that carbon dioxide isn't the only greenhouse gas measured. There are others - methane and nitrous oxide being only two.
While many people may know about the subject of Carbon Footprint, fewer know it's a subset of two larger subjects: Ecological Footprint and Life-Cycle Assessment (LCA). An ecological footprint is our demand on the earth's eco-system in total, and LCA is an assessment of a person or product's impact on the environment from its beginning to end. It's interesting to note that the gurus examining ecological footprints have determined that, at present, we require more than one earth to offset the effects of living on this planet. This means we're living in the red, and the LCA people look at the effects our existence has on the different stages of products including: raw material extraction, processing, manufacturing, distribution, use, maintenance and finally disposal (or recycling).
While most people think of a carbon footprint as the effect fossil fuels have on the environment, few people take the time to consider what effect one's mere existence has on that same environment, specifically the atmosphere. Years ago, after doing a search on the Internet, it came up that the biggest contributor of methane to the atmosphere were cows. Can you believe it? Cows! CO2 is another by-product of existence. Now, I'm not suggesting we stop exhaling, but just for posterity let's take a look at just how much CO2 is exhaled by humans every day. On average, each person exhales approximately 200 ml of CO2 each minute. That's 12 liters each hour and 288 liters of CO2 each day. Multiply that times the 6.9 billion people on this planet and you have just under 2 trillion liters of CO2 exhaled into the atmosphere each day by humans, and that's just humans. That doesn't take into account all the other species.
Fortunately, the ecosystem has a plan in place to deal with a carbon footprint. It's called trees, bushes, and plants. Contrary to popular belief, plants don't use up oxygen. Quite the contrary, plants give off oxygen and absorb CO2. That's why it's so important to curtail the amount of deforestation going on.
Of course, speaking about the foregoing human contribution to the eco-system is done in a tongue-in-cheek manner (although the math IS correct), and this isn't to suggest we all stop exhaling! The fact is that the human contribution to atmospheric CO2 from exhaling is about one-fifth that of fossil fuel. Still, maybe we should pause to give thought to the effects of adding more CO2 to the carbon footprint and the atmosphere, from whatever source, as we continue with deforestation.