The Arctic’s permafrost is melting in places, causing soil that is no longer frozen to release greenhouse gases and potentially speed global warming, according to U.N. scientists. The implications could be huge for the planet — about 14 percent of the world’s carbon is stored in the frozen soil. In light of all the recent scary reports about global warming, the silence from the Bush White House has been deafening. David Gergen, a former advisor to Bush the Elder and Bill Clinton, wrote this month, “The world is now looking to George W. Bush for personal leadership.”