According to 97 percent of climate scientists, climate warming is real and due to human activities. What can humans do to fight climate change? Some say that geoengineering—radical, large-scale technologies that would interfere with Earth's existing systems in ways that would counteract climate change—is the answer. One of the primary goals of geoengineering is to physically remove carbon dioxide from the atmosphere—through reforestation, carbon capture and sequestration, and/or cloud-weathering and space mirror technologies to deflect some of the sun's energy from Earth. The technologies come with huge risks: if we change the climate in one part of the world, how will that impact the climate in another part of the world?