The energy that powers the world comes mostly from coal, gas, and oil, and that’s led us to CO2 levels over 390 parts per billion now, and climate change. We can think of climate change as a design question: where do we want to end up? Impact studies tell us what will happen to the planet as we warm up—it's basically a litany of horrors. At a 1.5 degree increase, we'll lose 10 percent of species. At 2 degrees, we'll lose 90 percent of coral reefs. At 3 degrees, 1 to 4 billion people will face water shortages, leading to war across the planet.
We need to each understand the basic math behind energy and climate change so we can reach the right solutions. We need a massive shift to renewable energy, and we also need changes in our everyday lives. One first step is understanding your own carbon footprint.