Walkout heightens failure fears for climate marathon2009-12-14 COPENHAGEN (AFP) - Negotiators worked through the night Tuesday to prevent a UN climate summit from ending in catastrophic failure after developing nations staged a five-hour walkout and China accused the West of trickery. As the White House said Barack Obama wants a deal that imposes "meaningful steps" to combat global warming, ministers admitted they had to start making giant strides before 120 heads of state arrived for the summit's climax Friday. But their hopes were hit when Africa led a boycott by developing nations of working groups, only returning after securing guarantees...