Wall Street Journal: While the U.S. and others race to expand the use and production of biofuels, a growing body of scientific evidence suggests these gasoline alternatives will actually boost carbon-dioxide levels and thereby aggravate the problem of global warming. A study published in the latest issue of Science finds that corn-based ethanol, instead of reducing greenhouse-gas emissions by a hoped-for 20%, will nearly double the output of CO2 and other gases that trap the sun’s heat. A separate paper …