What is Your Lifetime Carbon Budget and Why Does It Matter?

According to Camila Domonoske of NPR, sales of electric pickup trucks that go vroom are going to boom. She speaks to consultant Alexander Edwards, who calculates that "2 million shoppers per year might entertain the idea of an electric pickup." The reasons have nothing to do with the environment; it's the torque, the turning force.

"Electric motors are remarkably good at delivering that exact kind of power. For some buyers, that could be persuasive. Electric vehicles have steering and handling advantages, too — hence the tank turns and crab walks of the promotional videos. And the massive weight of an electric vehicle is a boon for drivers hungry for traction."

Meanwhile, the editorial board at Bloomberg wants the incoming president to really push electric cars with bigger tax credits, cash-for-gas-powered-clunkers programs, and building half a million charging stations to support potentially 8.5 million electric vehicles on the road. That's a lot of cars and trucks.

Making all those cars and trucks will take a lot of steel, aluminum, and lithium, all of which have large upfront carbon emissions, or embodied carbon, probably between 12 tonnes for a car-sized EV to as much as 60 tonnes of CO2e for something like the Hummer EV. This is why I keep saying that electric cars won't save us; we simply don't have the headroom in the global carbon budget that we need to stay under to keep the global temperature from rising more than 1.5 degrees C. It's why I keep saying we shouldn't be investing in subsidies to buy electric cars but should be investing in things that make it possible for many people to live without them. And every time, I get comments like "Such hate! Talk about the concept of letting excellence be an enemy to good." It's so frustrating, how can I explain this?

Then I saw this tweet from Rosalind Readhead, who inspired me to start the 1.5 Degree Lifestyle Project, soon to be a book from New Society Publishers. She talks about us each having a lifetime carbon budget of 30 tonnes, and how electric cars or flights are real budget busters. In fact, a Hummer EV at 60 tonnes of CO2e embodied carbon is twice the budget before you even drive it off the lot. People responded to Rosalind's tweet with statements like "We need to focus on fossil fuels rather than being individually virtuous. This plays into the fossil fuel tactic of deflection." I get this argument a lot with the whole discussion of the 1.5-degree lifestyle, so let's follow through with the logic of this.

What is the Carbon Budget Per Person?

As explained by Zeke Hausfather of Carbon Brief, "The idea of a 'carbon budget' that ties an amount of future warming to a total amount of CO2 emissions is based on a strong relationship between cumulative emissions and temperatures in climate models." Temperature rise is proportional to the amount of CO2 in the atmosphere. The budget was one of the basic building blocks of the Paris agreement and has been shrinking ever since. At the beginning of 2020 budget numbers were:

• 985 Billion tonnes (Gt) CO2 for limiting warming to 2.0°C with a 66% probability
• 395 Gt CO2 for limiting warming to 1.5°C with a 50% probability
• 235 Gt CO2 for limiting warming to 1.5°C with a 66% possibility.

These are not per year or by 2030, these are cumulative, total emissions. In the most simplistic but equitable calculation, you just simply divide that by the number of people on the planet (7.8 million) and you get what is each of our fair shares.

This is obviously simplistic; nobody ever divided anything on this planet fairly or equitably, and it doesn't adjust for age; I shouldn't get the same amount of carbon to go through as someone a third my age. (There is a much more sophisticated calculator on Carbon Brief.) It is nothing more than a guideline and a different way of looking at things.

But when you do look at carbon this way, it no longer seems like such a good idea to throw money at electric cars that blow between half and two times the 30-tonne budget we should be aiming for. It seems much more logical to invest in making it easier to live without cars, with transit or cargo bikes and e-bikes and the infrastructure that supports and encourages them getting the big subsidies. Or with zoning laws that encourage walkable communities and 15-minute cities, so that most people don't even have to think about driving.

As I have noted before, a lot of things change when you start thinking about upfront or embodied carbon. When you start thinking about your share of the global carbon budget, it changes even more. I am not saying that everyone should or can live their entire lives counting their cumulative carbon budget, but that is what we have to do collectively, so it is a useful tool to keep in mind. And we are not going to succeed if everyone is hungry for the traction of a big heavy electric pickup truck.