Agence France-Presse: Scientists and economists Thursday urged US policymakers to pass laws to cut greenhouse gases as Senate prepares to debate a sweeping climate change bill that is opposed by the White House. Highlighting the United States’ failure to enact federal laws to cut greenhouse gas emissions, the Union of Concerned Scientists issued a statement signed by 1,700 experts calling for “swift and deep cuts.” “The longer we wait, the harder and more costly it will be to limit …