James Hansen, legendary for perceiving the threat of catastrophic climate change during his long career as NASA’s chief climatologist, delivered a Wrigley Lecture in February 2016 detailing the latest climate-change developments. He was also a speaker at the GreenBiz University conference, presented in partnership with The Sustainability Consortium and the Walton Sustainability Solutions Initiatives.

Hansen, a professor at the Columbia University Earth Institute, talked about how current policies are falling short, and what he thinks will work. He spoke about his plan for a carbon fee, calling it the only viable way to move away from fossil fuels that contribute to man-made climate change.

Click here to read his Thought Leader Series essay, which was featured in The Arizona Republic. The full video of his Wrigley Lecture can be viewed here.