Fending off damaging climate change is like a timed game of chess humanity can’t afford to lose. Our odds of avoiding checkmate improve significantly if we keep cumulative carbon dioxide (CO2) emissions under 350 gigatons between now and 2050. The problem is that if nothing changes, we will already deplete this CO2 “budget”—based on the Paris Agreement—by 2030.
A strategy known as “net zero,” which many companies, institutions, and governments are considering, buys the world time to transition to low-carbon technologies and for behavioral changes to take hold. The basic concept behind net zero is simple: reduce emissions aggressively and balance out the remaining CO2 with removals.
But there is a catch. The nature-based forms of removals available today cannot be relied on to keep CO2 permanently out of the atmosphere (forests could die, for example, leading to the release of once-stored CO2). They are in that sense temporary, so while important in slowing climate change, they can only serve as a stopgap.
The best course of action is a strategy of “true net zero” that combines highly aggressive emissions cuts with permanent removals. The challenge is that it requires nascent technologies, such as direct air capture, that are not yet available on a commercially relevant scale. Reaching a meaningful global capacity will take decades, and it will only be possible if we soon begin to grow the demand for permanent removals—rapidly.