There may be fewer metro areas in the U.S. in the near future. The federal government is proposing to downgrade 144 cities from the metropolitan statistical area designation. Under the proposal, a metro area would have to have at least 100,000 people compared with the 50,000-person threshold that was implemented more than 70 years ago. Statisticians say the proposal is a long time in coming, given that the U.S. population has more than doubled since 1950. Some officials whose cities are on the list to be downgraded don’t believe it will have a major impact. Others worry it will lead them to lose federal funds.