Presumably because getting the world to stop burning fossil fuels is an enormous effort, which we're not doing an especially good job of, so far. Carbon capture

Presumably because getting the world to stop burning fossil fuels is an enormous effort, which we're not doing an especially good job of, so far. Carbon capture isn't practical yet either (opinions differ on if it ever can be, and there certainly are some big problems to overcome), but that might still make it easier to pull off than ceasing our CO2-producing ways.