Will humans ever reverse climate change?

Stopping climate change will take a social, economic, and technological revolution the likes of which the world has never seen. But imagine, for a moment, that humanity eventually succeeds in not just flattening the curve of rising atmospheric carbon dioxide, but reversing it. How much of the climate heating greenhouse gas should we scrub out of the atmosphere if we’re one day able to do so?

Of the many fascinating questions Kim Stanley Robinson raises in The Ministry for the Future, a novel that explores a future in which humanity effectively solves the climate crisis, this is one that stuck with me the most. On its face, the question sounds so simple as to almost be trite. Surely there’s an ideal setting for Earth’s thermostat—a carbon concentration all the smart climate folks out there agree on?

At least, that’s what I had assumed. But when I posed the question to experts, I learned that there is little agreement on this matter from a physics perspective and even less consensus around what will be socially and economically feasible. “The answer,” Texas Tech University climate scientist Katharine Hayhoe told me, “is that we really don’t know.”