Who was president when U.S. greenhouse gas emissions rose most sharply since 1990, the U.N. benchmark year for action to fight climate change?
– George W. Bush (2001-2007)
– Bill Clinton (1993-2000)
– George H.W. Bush (1990-1992)
(I’m giving presidents responsibility for the full calendar year of their inauguration in January; official U.S. data are only available until 2007)

Answer — Bill Clinton (by a long way).

Many people might have thought the worst scorecard was by George W. Bush, who gave up plans to implement the 1997 Kyoto Protocol for cutting greenhouse gas emissions, signed by the Clinton administration but never submitted to a hostile Senate for ratification.

But emissions rose by more than twice as much in the Clinton years, when climate campaigner Al Gore was vice president, as during the combined years when two Bush presidents, father and son, were in the White House since 1990.

So is that legacy a problem for President Barack Obama, a Democrat like Clinton?

At U.N. negotiations on a new climate treaty due to be agreed in Copenhagen in December, many nations welcome promises by Obama of far tougher action than Bush for cutting greenhouse gas emissions. But there are nagging memories of unkept promises — Clinton’s administration agreed to cut U.S. emissions by 7 percent below 1990 levels by 2008-12 as part of the Kyoto Protocol. In 2000, Clinton’s last full year, U.S. emissions were 15 percent above 1990 levels.