Attenborough said he was encouraged by the action of young people around the world who are publicly fighting for climate justice.
We may have more to thank planetesimals for more than we realized.
The planet is now in a resource deficit for the rest of the year.
It's tricky to redefine what citizenship means in an era such as ours.
NASA's EPIC camera takes a photo every two hours, revealing how the planet would look to human eyes.
The 89-year-old will get back behind the mic to narrate the BBC's upcoming 'Planet Earth' sequel.