When I was about 15 years old, I started organizing around climate change, working with friends to organize teach-ins at high schools and middle schools around the region. At 18, I attended the United Nations Climate Conference in Peru in 2014, the meeting that preceded the Paris climate summit, where a landmark global agreement on climate change was signed. If I could go back in time, I would have never attended the conference — it aroused in me an overwhelming feeling of powerlessness and hopelessness that led me away from the climate movement for years. The huge jump in scale...