United Press International: A United Nations scientist struck back at climate change critics Saturday, saying the great weight of science still supports the findings of a landmark report. Achim Steiner, head of the U.N. Environment Program, wrote in an opinions piece published Saturday in the Turkish newspaper Today’s Zaman that critics who have seized on a mistake over the rate at which the Himalayan glaciers would melt are missing the big picture. The 2007 report from a United Nations-backed panel of …