In the spectacular large-scale projects he's famous for (such as "Waterfalls" in New York harbor), Olafur Eliasson creates art from a palette of space, distance, color and light. This idea-packed talk begins with an experiment in the nature of perception.

Known for big, attention-grabbing installations -- like his four towering waterfalls in New York's East River -- Olafur Eliasson has scaled down his latest project, Earth Speakr: an art platform for kids designed to spur budding climate activists to lead discussions on nature, conservation, pollution and more.

The climate crisis demands leadership at every level. Governments, cities and businesses are three key players in designing and implementing the necessary transition -- and putting climate back on the political and social agenda. Session 2 of the Countdown Global Launch, hosted by Al Gore and Jaden Smith, features Severn Cullis-Suzuki, Ursula vo...