Guest post by Mark Tercek, The Nature Conservancy's President and CEO.Earth Day is tomorrow. Yes, people and nature around the world face grim threats due to rising temperatures, increasingly frequent and intense natural disasters and increased demand for food, water, land and energy. But before you get too depressed, let me explain why this Earth Day, I’m optimistic. Poll after poll shows immensely broad and diverse support for conservation. We have seen a surge in protected areas around the world. More and more communities are incorporating nature into their planning to reduce risks from natural disasters. Outside the U.S., climate change is at the forefront of many national agendas and has transcended political divisions. And thanks to advances in science and technology, we know more about the environmental challenges we face than ever before—and how to address them. So what can we do to build on this momentum to keep April 22 as a day to celebrate? The complex challenges we face require a broad array of solutions. And I say the more solutions the better—it's encouraging to know that a diverse community of environmental NGOs is addressing these challenges from a variety of angles. While our approaches may differ, we are all working toward the same ultimate goal: a verdant, healthy planet where both people and nature thrive.