Net Zero
The point at which human greenhouse gas emissions are matched by an equal volume of removals, so atmospheric CO₂ stops rising.
Net zero is the state where annual greenhouse gas emissions are balanced by an equal volume of removals — natural or engineered — so the atmospheric concentration stops climbing. It is the first goal of any climate program and the boundary condition for the second one: getting the atmosphere back to pre-industrial chemistry. Reaching net zero requires electrifying combustion sources (electricity, vehicles, heat) and finding new processes for the non-combustion forty percent (cement chemistry, fertilizer synthesis, livestock, land use). But it is not the destination. Even at net zero, roughly 2,000 gigatons of legacy CO₂ remain in the atmosphere, continuing to warm the planet for millennia. Draining that stock is the work of carbon removal — what comes after net zero, not what ends with it.