The French probably have a word for it, and if the French don't, the Germans likely do. It's the word for a monumental accomplishment that simultaneously falls short of complete success and, in some ways, falters completely. Yet the door to success isn't shut—it's open and beckoning, with the fresh-baked scent of something wonderful wafting from the future. Complicated, right? But that's where we are after 195 countries spent two weeks forging an international climate agreement at the United Nations' 21st Conference of the Parties (COP21) in Paris last winter. 

The conference made history before it even began: 187 countries submitted commitments for reducing their greenhouse gas emissions before the negotiators arrived in Paris. That those commitments fall significantly short of what's needed, however, was lost on no one. And that shortcoming, in turn, helps explain one of the most extraordinary COP21 developments: the establishment of a more ambitious target of keeping total climate warming well below 2°C (and ideally less than 1.5°C). Add to that the official commitments to "reach global peaking of greenhouse gas emissions as soon as possible" and to achieve net-zero carbon emissions by the end of this century. For the first time ever, virtually all of the world's nations have agreed upon an ambitious strategy to address climate change.

At the 2015 U.N. climate change conference, 195 countries committed to replacing fossil fuels with clean, renewable energy sources. | Illustration by Jon Krause

In effect, the world has declared its intention to replace fossil fuels with clean, renewable energy sources, while also better managing our forests and how food is produced and consumed. The Paris climate accord puts fossil fuel corporations on notice that they can't continue business as usual. It also sends a powerful signal that, as President Barack Obama put it, "has the potential to unleash investment and innovation in clean energy at a scale we have never seen before." 

Yet we can't ignore the ways in which COP21 fell short. Besides the obvious gap between commitment and ambition, there is the fact that the commitments are not legally binding. Also, although developed nations promised at least $100 billion annually in public and private investment by 2020 to help poorer countries develop clean energy and respond to climate disruption, serious disparities still exist between the countries most responsible for the problem and the ones that will be most harmed by it. Unfortunately, provisions that appeared in earlier drafts for protecting human rights, including those of indigenous people, and workers' rights either vanished or were watered down.

But here's what's keeping the door to success open: The accord taps into fundamental truths about the transition from fossil fuels to clean energy—this journey is both irresistible and irreversible. The strongest provisions call for periodically ratcheting up each nation's commitments. A "global stocktake" will review countries' progress every five years, with nations recalibrating their ambitions based on advances in clean energy technology or financing (and perhaps with increased urgency due to the further effects of climate disruption). That's how the gap between action and ambition will be closed. 

What does this mean for the climate movement? First, without hundreds of thousands of people marching in the streets and working to replace dirty fuels with clean energy, the Paris agreement would not have been possible. Second, this agreement means that there's never been a better time to double down on pushing for climate action, climate justice, and clean energy. We need to do that not only to address the shortcomings of the Paris agreement but also to take full advantage of the opportunities it has created. The next years will be crucial. 

Our world is heading for a better, cleaner, healthier, safer future. There may be a fancy foreign word for that, but for now, I think we can settle on a simple one: progress.