Agence France-Presse: US Energy Secretary Steven Chu said Tuesday the Obama administration wanted to paint roofs an energy-reflecting white, as he took part in a climate change symposium in London. The Nobel laureate in physics called for a "new revolution" in energy generation to cut greenhouse gas emissions. But he warned there was no silver bullet for tackling climate change, and said a range of measures should be introduced, including painting flat roofs white. Making roads and roofs a …