This week in the Planet Earth Podcast: how carbon capture and storage works and why it's here to stay, the effect of floodplains on water pollution, and how exactly do you measure the thickness of polar ice from space? A pub isn't an obvious place for a discussion about taking carbon dioxide out of the atmosphere and storing it in rocks deep underground, but the venue for this week's Planet Earth Podcast isn't any old pub. This pub is set into the sandstone rock in the centre of Nottingham and is the perfect place to demonstrate exactly how the technology works. Richard Hollingham visits Ye Olde Trip to Jerusalem to see for himself...