Costing the Earth - Protecting the Past

Alice Roberts investigates the threats posed to our great historic sites by climate change. Is there anything we can do to save the most vulnerable properties from extreme weather and regular flooding? All over the world conservators and policy makers are pondering the implications of global warming for our most important heritage sites. Alice visits three sites to investigate possible responses to the problem. In Ireland she visits Newgrange, the stunning centrepiece of a Neolithic landscape which finds itself assaulted by regular flooding of the nearby River Boyne and ever more extreme rainstorms. Europe's greatest collection of Megalithic art is being eroded faster than ever and undiscovered archaeology is being ploughed into the ground as local farmers turn from farming cattle and sheep to the arable farming that suits the changing climate. At Rosslyn Chapel near Edinburgh the laser-scanners from Historic Scotland are part way through their ambitious attempt to record 3-D models of the pick of the World Heritage Sites. They have already fired lasers at the presidents' heads on Mount Rushmore and are set to visit Machu Picchu and Orkney's Skara Brae, an ancient village at imminent risk of destruction from rising sea levels and more frequent storms. Is all we can do really to record, scan, photograph and despair, or can our historic landscapes be saved with enough time, vision and money? On Exmoor the National Trust is devising a plan to manage an entire river from source to sea. The aim is to avoid another Boscastle-style disaster where sudden, unprecedented rainfall overwhelms a river and the historic sites on the coast below.