At the recent Group of 20 meeting in Hamburg, Germany, I witnessed a significant and positive turning point in the battle against climate change. Even as the world's biggest contributor to greenhouse gas emissions chose to stand on the sidelines, the 19 other countries — urged on by people power — pulled together and reaffirmed their commitment to the hard-won Paris Agreement.

As Greenpeace activists scaled a local bridge, the newly dubbed Group of 19 nations stood united against a now-isolated U.S. President Donald Trump. Their final joint communique labeled the historic Paris climate deal as "irreversible" and reaffirmed a shared commitment to push forward toward a low-carbon future. More than just a rebuttal of Trump's attempts to ignore the unfolding climate crisis, the move highlights the growing importance of the role other nations can and must play to keep the momentum going.

To put their words into action, the G-20 must now accelerate the global clean energy transition and set sail from Hamburg with an agenda of change. I'm in South Korea this week to see what's possible and to witness firsthand how people power has the ability to radically change national agendas and inspire global change.