Routes to a Carbon-Free World

Humans need to cut CO 2 emissions rapidly to limit global warming and prevent dangerous climate change. Policies adopted so far in countries worldwide are not enough. The good news is that there are many things we can do. First, we can save energy by using the most energy-efficient technologies and by changing our lifestyles. Second, we can use CO 2 -free energy sources, such as solar, wind, or hydropower. Third, we can invest in technologies that can remove CO 2 from the atmosphere. Finally, we can regrow forests all over the planet. Scientists imagine alternative future “scenarios” including different combinations of technology, energy, and lifestyle solutions. We know it is possible, but we need to act now to reduce CO 2 emissions, even if it means making hard choices.