A group of some 46,000 physicists urged the United States on Tuesday to dramatically improve its energy efficiency in the interest of becoming more energy independent, saving money, and staving off climate change. The group, the American Physical Society, said of such a program, “the opportunities are huge and the costs are small.” Smart folks. On the issue of climate, the group took the no-nonsense attitude you’d expect from a large group of professional scientists. “The physics and chemistry of the greenhouse-gas effect are well understood and beyond dispute. Science has also achieved an overwhelming consensus that the increase in greenhouse gases is largely of human origin,” the group said. They also concluded that with current or almost-on-the-market technologies, buildings could be made dramatically more efficient — enough to cut projected energy use in U.S. buildings 30 percent by 2030. The report recommended tougher state standards for commercial and residential buildings and also stressed the need for government to fund development of cheaper, more reliable batteries for electric cars.