Forget net-zero: to halt global heating, aim for net-negative

In Reykjavik, Iceland, a Climeworks factory located at the back of a power plant draws in ambient air and releases it as largely purified CO2 through ventilators. Halldor Kolbeins/AFP

In the fight against climate change, the lever every policymaker has been focusing on has been the reduction in (net) emissions. Curbing the rate at which greenhouse gases are pumped into the atmosphere clearly remains a priority. Yet every serious scientific analysis – in particular the latest IPCC report – agrees that a substantial amount of CO₂ must be removed from the atmosphere via negative-emission technologies if we want to have a reasonable chance of limiting the temperature increase by the end of the century to 1.5 to 2C above pre-industrial levels.

Negative-emission technologies range from the age-old method of planting trees to high-tech machines that will suck out carbon from the atmosphere directly. They also include bioenergy with carbon capture and storage (BECCS), which extracts energy from biomass by either burning or fermenting it and then capturing its CO₂. Unfortunately, despite being indispensable to remain within these temperature limits, such methods are receiving very little attention, and even less funding.