By Emma Farge GENEVA (Reuters) – Nuclear powers have criticized an effort led by the Marshall Islands at the United Nations to seek help on dealing with the consequences of nuclear testing, sources following the talks involving countries including the United States, Britain, Russia, India and China told Reuters. Pacific islanders, who are particularly threatened by rising sea levels from climate change, are becoming more vocal in seeking redress from former colonial powers and wealthy countries on environmental and climate issues which they say affect their human rights. This motion brought to…