“The history of Earth Day is pretty remarkable. The net result is 20 million people came out on the streets. It remains the largest civic day of action in human history. There’s no other country, no other world that ever had 20 million people coming out on the streets around a single issue. That was on April 22, 1970, and right after that, it became apparent with that many people that Congress and State legislators had to do something about it because, frankly, they were afraid of that many people all speaking in one voice.

The philosophy of Earth Day is very much about building a big movement, making sure it’s diverse, constantly improving the ways that people access information, and have access to mechanisms for legal relief.

Over the course of the next couple of decades it became year-round, it went internatio ...