Visualize How Much Carbon And CO2 Humans Emit

It's hard to picture exactly how much carbon we emit. One decent way to do it is to relate it to the carbon in forests.

A way to picture this that might be helpful is to think of it in terms of the amount of carbon in a forest. In the US, forests store roughly 18 kg of carbon per square meter (p 3). That's roughly 80 tons per acre.

The US also emits roughly 6.5 billion tons of CO2e per year. That's CO2e instead of carbon, so to convert you just divide by 3.67, which yields 6.5/3.67, or 1.8 billion tons of carbon per year.

Now...1.8 billion tons of carbon per year at 80 tons per acre means that we emit carbon equivalent to all of the carbon in 1,800,000,000/80, or 22,500,000 acres of forest per year. That's roughly the size of Indiana. Every year, the US emits as much carbon as is contained in a forest the size of Indiana.

That's all carbon in the trees, soil, etc. What about equating it to a forest fire instead? I can't find great numbers on the amount of carbon released in a forest fire. The three most relevant estimates I can find are ~5 tons per acre, ~8.5 tons per acre, and ~11 tons per acre. There seems to be a good bit of controversy on exactly how much of the forest's carbon is released in a fire, so I'll choose the lowest estimate...5 tons per acre.

Our total emissions were 1,800,000,000 tons. At 5 tons per acre, that's 1,800,000,000/5, or 360,000,000 acres. That's roughly twice the size of Texas. The US's emissions are equivalent to a forest the size of Texas burning every six months. That's a forest fire the size of Pennsylvania every month. That's just the US.

One final comparison...according to the '80 tons per acre' source from earlier, the trees in a US forest contain roughly 25 tons of carbon per acre. Imagine we grow forests, chop down trees, and bury them to offset our emissions. We'd need 1,800,000,000/25, or 72,000,000 acres of this per year. That's roughly the size of Arizona. We would need to cut down and bury all trees in a forest the size of Arizona each year to offset our emissions.

However...remember that trees take a while to grow...say 20 years for this. That would mean that at any given time, we would need 20 Arizonas worth of forests maintained specifically for us to chop down and bury all trees if we wanted to offset our emissions. For reference, that is roughly the size of the United States minus Alaska and Texas. That's just to offset the US's emissions. We emit a lot of carbon...

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