A Right Turn for Earth Day

One of the thickest chapters in human history could be titled "It Seemed Like a Good Idea at the Time." Over the centuries, our species has taken plenty of wrong turns -- often because we simply didn't know any better.

Well, hindsight may be 20/20, but that doesn't mean we can use it to change the past. What we can do, though, is learn from the past to make the future better. It turns out that a big part of what humans call progress is having the good sense to stop doing dumb things once we wise up.

This Earth Day, we mark a major milestone in stopping one of the most dangerous mistakes our species has ever made: Digging up and burning enough fossil fuels to change our planet's climate. Today at the United Nations, more than 150 governments will attend the signing ceremony for the groundbreaking climate agreement that was negotiated and adopted in Paris at the end of last year. The agreement was basically the whole world's way of saying with one voice: "Wrecking our climate by burning fossil fuels is crazy and it's got to stop!"

That was not even half a year ago, but the message is reverberating around the world. Here in the U.S., the biggest single source of climate pollution, coal-fired power, is on the ropes -- with the world's largest coal-mining firm declaring bankruptcy just last week. Cities like San Diego and Burlington, VT, are committing to 100 percent clean energy, while both New York State and Oregon plan to completely eliminate coal. Wind and solar are booming, and almost 400,000 people have put deposits down on Tesla's as-yet-unreleased Model 3 EV.

Meanwhile, China may already have reached peak coal as it accelerates its clean-energy development. India is on track to install more than 100 gigawatts of solar power in the next six years and is saying that solar is already cheaper than coal. And around the world, renewables accounted for half of the new electric capacity installed last year.

A year ago, even an incorrigible optimist like me wouldn't have guessed that this is where we'd be today. It's definitely reason to celebrate. But... even with the Paris agreement and all the momentum we've gained, we're still not where we need to be if we're going to save our climate.

It may be governments that are signing the Paris agreement today, but that wouldn't be happening if it weren't for millions of ordinary people who care making the future better. So let's celebrate this milestone with the same kind of grassroots activism that's helped us get this far.

As coal companies go bankrupt, they could leave American taxpayers forced to bail them out by paying for the cleanup of abandoned mines. Tell the Department of the Interior to end "self-bonding" that could let these polluters off the hook.