The numbers behind offsetting emissions

This might lean ever so slightly in the politics territory, but here’s a fun calculation. Was just thinking about how big a pile of carbon would I need to offset my CO₂ contributions while on the walk.

Ideally, the CO₂ contributions should be put back underground, so the first idea would be to just cut down bury some trees (after all, once grown, trees aren’t being much of a net CO₂ scrub) – but that would be wrong. Charcoal — being pure carbon and much more stable than biomass — would be much better. Sure, you’ve got to turn wood into charcoal before you do anything with it, but the process of turning wood into charcoal doesn’t produce additional CO₂. This means: charcoal is the way to go.

Now that we know our preferred form of carbon, let’s take a look at the numbers:

  •  EU’s CO2 emissions are ~6.4 tons per year per capita. USA is 16.5. (using data for 2014).
  • Carbon represents 27.3% of CO2 by weight.
  • Density-wise, charcoal clocks between .2 and .6 tons per m3.

If you wanted to sequester the amount of carbon “you” are responsible for, the pile of carbon you’d have to manage would weigh ~1.75 metric tons (4.5 metric tons if you’re in USA). This translates to a nice 2.9 – 8.7 m³ (7.5 – 22 m³ for USA/NA in general) pile of charcoal to bury somewhere at the end of every year.

This, of course, excludes emissions related to cutting down trees, reforestation (!) and transportation; we also assume that charcoal production is using excess power from the wind farms on days when there’s too much wind. The good news, though, is this: most of the per-capita emissions is produced by companies. If you only wanted to deal with the emissions that you cause directly, the pile would probably be much smaller.

Emissions per capita stuff stolen from here.