What gets measured gets done; particularly if you make it public. Family carbon audit for 2018.


A grand total of 29.55 metric tons of CO2 for the two of us, 14.78 per person.

This is horrific. The cars. Good word the cars.

I had thought that my flying would be far-and-wide the largest issue. Since I work remotely for an international firm, I fly atlantic a few times a year.

Those flights, it turns out, pale next to the power of my Chevy Silverado and the 2004 Ford Focus. The issue seems to be the level of inefficiency of these vehicles, particularly the truck, and how much long distance driving we do. When we did this audit, both of us biked to work, so the emissions here is almost entirely from out-of-town trips.

Food is non-negligible, but smaller than I expected.

Natural gas - the primary source of heating in the house - is more than I expected. The house we rent uses natural gas for the stove, HVAC and water heating.

Electricity is a big portion as well; A/C makes the midwest livable. Unfortunately, the City of Columbia almost exclusively burns coal and natural gas for it’s power needs. Just about 92% of the power mix of the city utility is gas and coal.


After this audit, we decided to make several changes:

  • Look into replacing the Ford Focus with a more fuel efficient vehicle
  • Only drive the truck when hauling construction loads or towing
  • Replace thermostat with a Nest thermostat
  • Review our eating habits
  • Explore if the city has any options for low carbon electricity

For completeness, things we were already doing at this point included:

  • No beef or pork
  • Cold water laundry
  • Low flow shower fixture
  • No car commute

Why carbon audit?

Global warming is this big daunting thing. It can feel stressful because.. what can you and I as individuals do?

Many of the required solutions involve politics or international negotiations! Sometimes it feels impossible to even ponder the work ahead of us.

Looking on the micro level: my own house, my cars, the dinners I cook gives me something I can control. While it may be a small drop in a large bucket, it is a drop my family is in control of.

It’s also incredibly informative!


  • Go through calendar, find all flights, calculate CO2 impact via ICAO
  • Get natural gas consumption from utility, concert to cubic feet, multiply by 53.12
  • Get electricity from utility, multiply by utility energy mix emissions (this was kind of a PITA)
  • Get miles driven for each vehicle, multiply by gallons per mile, multiply by CO2 per gallon
  • Write up estimated weekly menu, calculate emissions

I started looking at stuff like clothes consumption, since you hear a lot about the impact of cotton but.. It seems like the impact of clothes consumption is really small for us, like less than one percent.

Reading about it, it seems the primary CO2 impact of clothes is from heated washing. Since I already count water heating and electricity, I think the current summary does an ok job as a rough approximation.

See also