What were the biggest stories on this earth podcast in 2013? I'm glad I asked:

We had the new rush for oil in the Arctic and other extreme places. Scientists offered new hope for bringing back extinct species like the passenger pigeon. And the new Pope Francis began talking up the environment, just like his saintly namesake.

Plastic litter got just about everywhere, while ants stowed away on ships to spread around the globe. Cities turn out to follow mathematical rules and our dandruff shampoo turns out to be poisoning plants. The best places to put wind or solar power are not necessarily the windiest or the sunniest but rather wherever they cut the most pollution.

Junk piles of old gadgets, TVs and other electronics remain a large and growing problem. And life persists almost everywhere we look on this planet, from the skies above to the deepest spots in the oceans.

But the biggest story of 2013 is an ongoing one: climate change. This past May, concentrations of CO2 in the atmosphere reached levels never before experienced by us, Homo sapiens. We're living in a whole new world. In this new year of 2014 and beyond.

—David Biello

[The above text is a transcript of this podcast.]