[Below is the original script. Some changes may have been made during the recording of this audio podcast.]

Earth Day gets more press but the real environmental holiday this week is National Arbor Day, today! April 24th.

Trees do a lot for us: provide wood, improve health, even clean up the air.

And maybe get us out of a little problem we've created called climate change.

That's because carbon dioxide—the main greenhouse gas driving climate change—is plant food. The leaves of trees suck in sunlight and then chemically convert CO2 to carbohydrates. This process called photosynthesis sustains almost all life on Earth.

So the answer to climate change is simple, right? Just plant more trees.

Well…it’s not that easy. Trees have a habit of dying and decomposing, which puts a lot of that CO2 back into the atmosphere. And since our goal is to pull CO2 from the atmosphere permanently, trees are not the best solution.

But we have a lot to do with that too. Humans cut down a lot of trees, making deforestation the second biggest source of the 30 billion metric tons of CO2 put into the atmosphere yearly by us. Planting trees might not solve global warming, but cutting back on cutting down trees would be a big help.

—David Biello