“50 years ago, 20 million young people protested about the damage to our Earth. Over the past 5 decades, a lot has happened. Our ozone layer is healing, renewable energy is booming worldwide, environmental awareness has never been higher. But some risks are even more acute than before,” said Denis Hayes, coordinator of the first Earth Day and founder of Earth Day Network, in a video message at a recent Wilson Center event commemorating the 50th Earth Day.