UNITED NATIONS -- An international panel of scientists presented the United Nations with a sweeping, detailed plan on Tuesday to combat climate change -- a challenge, it said, "to which civilization must rise." Failure would produce a turbulent 21st century of weather extremes, spreading drought and disease, expanding oceans and displaced coastal populations, it said. "The increasing numbers of environmental refugees as sea levels rise and storm surges increase will be in the tens of millions," panel co-chair Rosina Bierbaum, a University of Michigan ecologist, told reporters. After a two-year study, the 18-member group, representing 11 nations, offered scores of...