I first realized the fundamental truth in Henry Ford’s statement: “Whether you think you can or you think you can’t, you’re usually right” when, during my first press conference as Executive Secretary of the UN Climate Change Convention, I was asked whether I thought a global agreement on climate change was possible. I blurted out: “Not in my lifetime!” Those words accurately reflected the prevailing mood in early 2010. But as soon as I said them, I realized that if we were to achieve a global deal, I was going to have to change my attitude.

To begin with, I personally would have to become a beacon of possibility, modeling the determined mindset that such an agreement would need. Then I would have to work out to ever-increasing concentric circles of influence (first my team at the secretariat, then the large group of country representatives, and then beyond them to the even larger group of stakeholders), enticing everyone toward a positive mindset. The journey was long, difficult, and involved thousands of people working together in a myriad of ways—but a few years after that press conference, we secured the historic Paris Agreement on climate change in December 2015. That agreement, co-written and negotiated with 196 governments, was the world’s first (and to this day the only) legally binding business plan designed specifically to protect people from dangerous climate change. It was a moment of great hope for so many. But a business plan is only worth its salt if it is enacted in a timely manner.

Read the full commentary in The Bulletin of the Atomic Scientists