The Rio+20 Earth Summit, coming during a prolonged global economic downturn, is a rare opportunity to reconnect with our hopes for the world. It is a chance to think beyond the acute phase of the financial crisis about how we want to embed sustainable development and stability into the decision making of governments, businesses, and civil society.

As delegates head to this historic event, RSPB and Green Alliance have asked leaders from politics, business, NGOs, economics, science and the youth movement, including Deputy Prime Minister Nick Clegg who will be representing the UK, to give their views.

Although progress has been made since 1992, sustainable development has not gained the traction those at the original summit would have hoped. The authors give opinions about why this is, the lessons we have learned and where we go next. Taken together they make a powerful case for sustainable development being at the centre of any new settlement that emerges from the current economic crisis.