What to do about the excess CO2 in our atmosphere that will remain for hundreds of years --even as we transition to renewable energy? The impact on Earth's climate is already obvious and will continue. To reduce the damage, we have to find a way to deal with that long-term CO2 in the atmosphere. Various "solutions," commonly known as types of geoengineering, have been proposed. Here, **Professor Daniel Cziczo** explains the CO2 problem and the three major types of geoengineering. We learn why the only viable approach is CO2 sequestration --pulling the CO2 out of the atmosphere.