Environmental groups believe John Podesta will be a force for change on climate issues at the White House. The groups argue that for must of Obama’s years in office, an administration that took power at the height of the recession has prioritized helping the economy over other goals. That’s created an uphill climb for advocates pushing the White House to take a tougher line in reducing carbon emissions and cleaning up polluters. Podesta’s arrival as a White House adviser, which comes as unemployment hits a low point under Obama, is a pivotal moment, activists predict. “The most significant thing about...