Climate change poses grave risks to humanity; confronting it will require a massive transformation of the world’s energy systems. Fossil fuels like oil and gas still shape global geopolitics and provide energy to billions, but burning those fuels causes catastrophic changes to the climate. To avoid worsening climate change, nations need to speed the transition toward clean energy. In addition to investing in clean energy to reduce emissions, countries also need to build resilience to worsening extremes fueled by climate change—record-setting heat waves, raging wildfires, deepening droughts, damaging floods, and intensifying storms. The program on Energy Security and Climate Change at the Council on Foreign Relations informs scientists, business leaders, policymakers, and the public about how to navigate tomorrow’s energy and environment landscapes.