In 1992 the world's biggest ever political gathering - the Rio
Earth Summit - marked one of the first times that world leaders met
to discuss the environment. Twenty years later, they're meeting
again for Rio+20 to see how well they've done - and how much more
they need to do. In response, A Rocha, Tearfund, New Frontiers and
Jubilee+ have set up a series of discussion evenings ...