Look up at the Empire State Building from the streets of Manhattan, and you probably will not realise there is a revolution going on inside. The towering building is receiving a radical “green makeover” that will cut its energy use and greenhouse gas emissions by nearly 40 per cent, and make it a pioneer in the use of new environmentally sound practices from cleaning to “green” pest control.

The Empire State is just one example – some of the world’s most historic buildings, including the UN headquarters and Balmoral Castle, the Scottish residence of the UK royal family, are being overhauled to reduce their environmental impact.