The concept of net-zero emissions refers to the process of achieving an overall balance between, on one side, all man-made greenhouse gas emissions, and on the other, the greenhouse gas emissions that are taken out of the atmosphere. This process is realized thanks to a series of reduction measures.
To achieve net-zero emissions, all human activities causing GHG emissions (such as fossil-fueled vehicles and factories) need first to be reduced as close to zero as possible. Then, even where there will be no more direct or indirect greenhouse gas emissions from fossil fuels, it will still be necessary to deal with the emissions already present in the atmosphere (the difference between zero and net-zero emissions). To meet the 1.5°C global warming target in the Paris Agreement, global carbon emissions should reach net-zero around mid-century.