Reservoir power: this is Kielder in Northumberland, the UK's daddy of them all. Photograph: Chris Leachman /Alamy

A 'Stop HS2' sign at the roadside in Drayton Bassett, Staffordshire. Photograph: David Jones/PA

Decc's 2050 calculator tool. Photograph: Decc

No longer quite the good deal they were for private homeowners; but solar panels on a city region scale would bring big dividends, according to the report. Photograph: Simon Burt/PA

Clouds forming in the wakes of the front row of wind turbines of Horns Rev wind farm, Denmark. Photograph: Aeolus

A beehive at the National Trust's Sissinghurst Castle in Kent. Photograph: David Sellman/National Trust/NTPL

A view of the Merced river, which flows through Yosemite valley. Taken by Carleton Watkins in 1861. Credit: JP Getty Museum

Water shortages: Ardingly Resevoir in West Sussex. Photograph: Gareth Fuller/PA

Arctic swans in flight. Photograph: Philippa Scott/Wildfowl & Wetlands Trust (WWT)

'Today’s failed economic order is designed to serve the interests of the City of London’s 1%'. Photograph: Adrian Dennis/AFP/Getty Images

Old coal mine sites can be made impressively green. Cronton is hoping to prove that point. Photograph: Christopher Furlong/Getty Images

Wind turbines In Llandinam, Wales. Photograph: Andrew Drysdale/Rex Features

Could air-traffic control become computerised? Photograph: Darren Staples/Reuters

MP Joan Walley at Johnson Tiles as Stoke on Trent signed up for the 10:10 climate Campaign. Photograph: Christopher Thomond for the Guardian

South African Foreign Minister Maite Nkoana-Mashabane, President of the 17th Conference of the Parties (COP17), gives a press conference on December 9, 2011 during the UN Framework Convention on Climate Change (UNFCCC) in Durban, South Africa. Photograph: Jenny Bates for The Guardian