I think that a big problem in getting people to care about carbon dioxide pollution is how abstract it is. It is a transparent, odorless, non-toxic gas that is already naturally occurring in the environment. We don’t see it, feel it, touch it, or experience it in any substantive way in our daily lives (see ‘Salience’ on this page) even though it is causing a global calamity. So I thought that I would go through a quick thought experiment that allows one to really visualize how much of this stuff we are producing.
In 2011, each American’s share of carbon dioxide pollution (and equivalents like methane) added up to about 24 metric tons. This isn’t an amount that is easy to think about. Our daily lives revolve around things that weigh pounds or kilograms, and we don’t often think about weight at all when it comes to gases. So though this is a good accounting method for scientists to measure carbon pollution, it isn’t useful for visualizing it. So we’ll describe it in two other ways to be able to better picture what we are doing.
As a gas at normal temperature and pressure (like the air around us), how much space would 24 tons of CO2 fill up? A quick conversion from weight to volume (calculator here) shows that the CO2 per American per year is about 450,000 cubic feet (13,000 cubic meters). This still isn’t a number that we can visualize, so lets imagine that we replaced all the air inside of a building with the CO2 that one person produces in a year. It could completely fill the living space of a 40,000 square foot building with 10′ ceilings, like the mansion below.
Or it could completely fill up a 20,000 foot warehouse with 20′ tall ceilings, like this one:
To reiterate, this is how much CO2 is produced per person each and every year. It is an absolutely enormous amount.
Or lets look at it another way. If one took that 24 tons of CO2 gas and cooled it enough, it would freeze and give you dry ice. Dry ice looks a lot like regular water ice, but it is a bit more dense. If you made one ton cubes of CO2 ice, each cube would be a bit less than 3′ (1 meter) on each side. 24 tons of dry ice would fill 530 cubic feet (15 cubic meters), enough to fill a large moving van.
When one thinks about it this way, it really starts to put things in perspective. Because our current economies are so dependent on fossil fuels, and these fuels give off CO2 when they are burned for energy, almost every activity we do produces carbon dioxide. We need to keep this in mind, and not just think about the physical things that we touch that were produced with oil, like plastic products. Each mile traveled, each service used, they all produce carbon dioxide. We are starting to decarbonize our economies, meaning that the carbon pollution for each activity is decreasing. But we need to keep the primary goal front and center, to get the net level of CO2 that humanity produces down close to zero.