The Maldives, an island archipelago stretching 900 kilometers north to south across the Indian ocean, has a tiny population. But after four days here, I’m convinced it will play an absolutely crucial role on October 24, and in the climate negotiations that follow.

Partly that’s because it carries so much moral authority. Low to the water, the Maldives could become uninhabitable if sea level rises unchecked. Worse, the coral reefs that surround each island are already dying off because of rising water temperatures—and those reefs provide not only income from tourists, but more fundamentally the protection against pounding waves. The country’s dynamic new president Mohammed Nasheed has already captured the imagination of the world by announcing that his country will set aside money in its budget each year to buy a new homeland if its old one becomes unliveable.

But that’s the dark side. The bright side is that the Maldives is a nation full of incredibly bright and committed people, many of them young, who have already led a democratic transformation in their own land and are now ready to lend their talents to the global fight. Together we soon hit on a strategy for October 24: the biggest underwater demonstration in history. At least 350 divers will descend to the reef with banners and signs on October 24—and that dramatic picture will, I’m convinced, be seen and felt across the world.

I don’t really want to leave, but I’m confident that Zaheena and Shauna and Azeez and many many others will carry the work forward to October and beyond. Yesterday I got a half an hour away from interviews and speeches to snorkel in the lagoon at the extraordinary Banyan Tree Vabbinfaru hotel near the capital of Male. It was very sad to see the remains of dead coral littering the sea floor from the last big bleaching incident—but incredibly encouraging to see newly planted coral gardens springing up, tended by Maldivians and tourists alike. A great sea turtle swum slowly by, and the environmentalist Mr. Azeez told us they might live 120 years. If we do our job right, she—and all the people of the Maldives—will be able to live out their lives in this most marvelous of places.