After a court order and four years late, Bush administration scientists issue an assessment. President Bush's top science advisors issued a comprehensive report Thursday that for the first time endorses what most scientific experts have long asserted: that greenhouse gases from fossil fuel combustion "are very likely the single largest cause" of Earth's warming. The 271-page report could undercut opposition to the more aggressive provisions of climate legislation, which is to be debated in the Senate next week. The Bush administration had long resisted a congressional mandate, the 1990 Global Change Research Act, requiring the White House to report every...