Washington Post: FOR TWO YEARS, the Danish capital of Copenhagen has been a beacon for environmentalists seeking a breakthrough international treaty on climate change. But with the long-awaited Copenhagen conference now just weeks away, it has become clear that the talks will not produce a grand, new accord mandating global reductions in carbon emissions. The United Nations’ envoy conceded as much last week in Barcelona, the site of the last formal talks before Copenhagen. According to some, the …