The world's population is due to hit seven billion next week - cause for joy or concern?
BBC World Service Online
Why we might not see a new deal on climate change until 2020.
The environmental battles over the paper industry, plus urban design and the London riots.
What would we do if it turned out there was more than one planet like Earth?
It's 40 years since the birth of the green movement. How has it fared? We find out.