COPENHAGEN (AFP) – UN chief Ban Ki-moon said world leaders faced a "defining moment in history" as they balanced their nation's interests with a global clamour to halt the juggernaut of climate change. With just over three days left to broker one of the most ambitious, yet also fiendishly complex, deals in human history, conference chair Denmark appealed for all sides to embrace the spirit of compromise. But China and the United States -- the world's two biggest carbon polluters -- brushed aside European calls for concessions on emissions reductions, the thorniest issue of all. Related article: UN system to...