Carbon emissions, mainly carbon dioxide, are only one of many things that are important to consider in a sustainable society, but with the looming problem of climate change, they make a good starting point. Looking at carbon emissions allows a person to evaluate their impact with just one number, and this number is usually associated with all those other things that we care about in terms of total consumption, as well as the health of ecosystems and people. Carbon emissions are much higher than they should be throughout the developed world, but are even higher in the US and Canada. These two countries have bigger distances to travel, bigger homes, bigger cars, and in many cases bigger heating requirements.
The US and Canada have very similar consumption, so we will consider them together here. Though estimates vary somewhat, we’ll use numbers from a 2011 study by Jones and Kammen that really breaks down where all those emissions come from. They show that in the US, each person’s share of emissions is 24 metric tons of carbon dioxide per year. Of that, about 20 tons (80%), is tied directly to our household consumption while the rest is things like government spending on infrastructure, military, etc. So this 20 tons per person is all tied to our lifestyles, in how we live, travel, what we buy, where we go. In order to stop climate change, we need to get to a point where we are producing no more than about 2 tons per person, so a 90% reduction is the work that we have in front of us.