In terms of COP21, the ISIS bombings backfired and there was a boomerang effect. The sympathetic eyes of the entire world were on Paris, which gave an enormous and unprecedented media boost to the climate conference and treaty talks.

We must also ensure that there are low-cost training and continuing education opportunities for workers to transition from the fossil fuel industry into good, green-collar union jobs. We need a just and fair transition so that working people, their families and communities are protected and supported as we move toward a clean energy economy.

Environmental degradation is a root cause of migration to California from Central America. And immigrant communities are not protected from socioeconomic vulnerability or the impacts of climate change in the U.S.

We're not organizing another march in New York City this year. Setting aside Star Wars and the Godfather, sequels are rarely better, and successful social movements rarely use the same tactic over and over again. Instead, we're mobilizing this year in Paris and around the world.

The burning of fossil fuels has not only changed the way we live and work, it has also changed our planet, so we must now change once again the way we do business. The cost of not doing so is too high -- if we go on as we are, we jeopardize national and global security and economic prosperity.

The next decade is decisive because trajectory counts for so much; if we bend it now, we may slide the car to a halt with just the front tires hanging off the cliff. But if we sail on for a few more years, it's pretty clear we're fast and furiously going airborne -- that's what happens when, say, Arctic permafrost starts to melt in earnest, releasing clouds of methane.