As Kermit the Frog once said — it’s not easy being green. Amid challenges like pollution, deforestation and climate change, engaging with environmental problems can feel like an overwhelming task. To mark Earth Day, we explore some of the ways, big and small, people are working to do just that.

Also on this week’s show:

• How a recent landmark study uncovered a hidden – and huge – source of air pollution.
• We talk with Chicago weatherman Tom Skilling on his decision to speak openly about climate change on the air.
• A look back at Population Bomb, the doom-and-gloom book from 1968 that helped shape the debate on saving the planet.
• Environmental scientist Halina Brown says saving the earth means cutting down what we buy.
• We ask a range of people about what “being green” means to them.