Net zero refers to balancing the amount of greenhouse gases released into the atmosphere from human activity, against the amount removed from the atmosphere. Usually this refers to CO2, but the same principles can be applied to other greenhouse gases.
Ideally this balance is achieved through implementing practices that produce no or little greenhouse gases. Such practices may include electrification of vehicles or improving the efficiency of heating to reduce the amount of energy require to power buildings.
Achieving net zero is key to preventing global temperature rises
However, completely cutting emissions within the time frame is not possible, or always practical, and instead offsetting (where greenhouse gases are purposefully removed from the atmosphere and stored elsewhere) is used. Common offsetting practices include planting forests to act as carbon sinks and direct sequestration of carbon (where technologies, such as direct air capture, extract CO2 from the atmosphere and store it in deep geological repositories).
Achieving net zero is key to preventing global temperature rises. The 2015 Paris Agreement saw 197 countries agree to limiting global warming to 1.5C, if 1.5C is to be achieve CO2 emissions must be cut. If not C02-induced global warming can be expected to continue for decades to come.