It's simple to mop carbon dioxide out of the air, but it could cost a lot of money. In the second of three features on the carbon challenge, Nicola Jones talks with the scientists pursuing this strategy

We will probably overshoot our current climate targets, so policies of adaptation and recovery need much more attention, say Martin Parry, Jason Lowe and Clair Hanson

Economist Nicholas Stern's latest book is a rare and masterly synthesis of climate-change science and economics