WASHINGTON — The short-term plan to reduce greenhouse gas emissions that President Obama outlined this week is achievable with some new programs and better management of existing ones, the new energy secretary, Ernest J. Moniz, said in an interview on Thursday. But he said reaching a longer-term goal would require bigger reductions as well as action from Congress.

When Mr. Obama first ran for president, he pledged to reduce greenhouse gas emissions in the United States 80 percent by 2050, compared with 1990 levels.

Mr. Obama’s interim goal, for 2020, is a 17 percent reduction in global warming gas emissions compared with 2005. The 2020 goal is already half achieved, Dr. Moniz said, and achieving the rest will require faster fulfillment of new appliance efficiency standards, among other steps. Many of those standards are stuck in a bottleneck at the Office of Management and Budget, which evaluates the costs and benefits of proposed regulations.

“I think the president’s commitment will provide the spur to O.M.B. and the Energy Department to move smartly on these,” Dr. Moniz said.