The article is talking about annual CO2 emissions, not total CO2 levels. CO2 levels and their rate of increase are a lagging indicator; it takes many years for

The article is talking about annual CO2 emissions, not total CO2 levels. CO2 levels and their rate of increase are a lagging indicator; it takes many years for a reduction in emissions to show up in CO2 levels. The models all assume that CO2 emissions will continue to increase; the main difference in the assumptions is how fast emissions are assumed to increase.