The United States is back in the Paris climate accord, but the depth of its commitment will become clear only in the next two weeks, when President Joe Biden unveils the details of the nation’s pledge for reducing greenhouse gas pollution. President Barack Obama pledged that the United States would cut emissions 26 to 28 percent by 2025, a goal the nation is not quite on track to meet. But environmental advocates are pushing for Biden to set a goal of at least a 50 percent cut in U.S. emissions by 2030, based on a slew of recent studies, including research by the United Nations and the National Academies of Science , showing that a 50 percent target is both necessary and achievable. On Tuesday, […]