The term “time value of carbon” is not used a great deal, but it is critical to understanding the concepts of embodied or upfront carbon emissions that we bang on about here at Treehugger. That’s why a tweet from climate scientist Jonathan Foley, who is the executive director of Project Drawdown, caught my eye:

As we have noted before in “Every Ounce of CO2 Emissions Adds to Global Warming,” emissions are cumulative. This is why upfront carbon emissions are so important—they are happening now and bash up against the ceiling of the carbon budget which is getting smaller every day.

And we have to stop thinking about this just in terms of buildings; it’s in everything we make and use.

The term “time value of carbon” is not often used. It shows up in the title of an article by embodied carbon pioneer Larry Strain but he never mentions the term itself again, explaining:

Jonathan Foley

We will need to do everything we can to cut emissions in half during this decade. That means no more waiting. No more delays. Not even well-intended ones, including waiting for better technologies that can help reduce emissions a little better. 

Accounting and investment firms are using it, probably because it reminds them of the time value of money (TVM). Investment firm Generation does a good job of explaining it:

Foley points to an article he wrote in early 2021 with another twist: To stop climate change, time is as important as tech. He explains the principle of the carbon budget and what he calls the carbon law, which demands we cut emissions in half in this decade.

In response to those who believe that tech will save us, he notes, “We have to start with tools on hand, and not wait for new ones that may (or may not) appear in the future.”

Foley concludes: “Time is as important as tech.”

Strain writes in a report, “When you save matters, what you build matters, what you don’t build matters more.”

I have noted many times that this isn’t just about buildings, it’s about everything from cars and computers to containers full of stuff we don’t need. When you look at the world through the lens of embodied carbon, everything changes. The same could be said about TVC: It changes the way you think about things.

Here we have investment advisors, accountants, climate scientists, and architects all talking about the time value of carbon—the “now” carbon being added to that big ledger in the sky, all pointing out that emissions cut today are worth more than emissions cuts in the future.

As Foley says, time is the crucial parameter here and we are quickly running out of it.