In countries like Germany and Japan, people are moving from smaller to larger cities because they have stronger economies with a greater variety of better-paying jobs.
Sound familiar? But many people stay stuck in shrinking cities, which grow steadily older and beyond revival.
While acknowledging that many cities are losing population, The Economist magazine argues for managing decline rather than trying to stop it.
It says in such cases the best policy may be to acquire empty offices and homes, knock them down and return the land to nature.
The magazine cites the eastern German city of Dessau-Rosslau and Pittsburgh in America where this has happened.
Cities lose people because of migration and demographic change and Dessau-Rosslau suffered from both. In the last eight years its population has dropped 10,000 to 81,500. It first tried to revive itself by building new homes, offices and shopping centres, but the population continued to plunge. Buildings fell out of use and some were demolished in piecemeal fashion.
In a radical move in 2002, Dessau-Rosslau decided it wouldn't decline erratically but plan for its own destruction by shoring up its more successful neighbourhoods while demolitions took place elsewhere. Buildings would give way to a broad "landscape zone", with grassy meadows cut once or twice a year. Small plots, 20m by 20m, would be given to all those who had plans to use them.
Although everything has not gone to plan, demolition has worked and many apartment blocks have come down, helped by low rates of home ownership.
It is acknowledged that co-ordination is harder where there are many landlords.
Now people pick wild flowers in the meadows where buildings once stood.
This example is having a knock-on effect. Inspired by Dessau-Rosslau, nearby German cities are also pulling buildings down, getting rid of post-war apartments on their fringes while prettifying their mediaeval cores.
The Economist says demolition crews have also been at work in some of the most severely depleted Japanese towns and in the American Midwest, where the process is known as "right-sizing".
The magazine notes that Pittsburgh, once a declining industrial city, has enthusiastically bulldozed houses and factories, particularly along its waterfront, and replaced them with parks. It has even started to grow again, though that is probably mostly thanks to its thriving universities.
So how could things pan out in Whanganui if it followed Dessau-Rosslau or Pittsburgh? It would be radical, but we could downsize the inner-city retail zone, demolish unused buildings and create a green zone on the perimeter.
All this flies in the face of ongoing efforts to promote the city's attributes to attract new residents. And there is no reason why these should not continue, while being aware that we are competing with every other city and town, which are trying just as hard.
It's a big challenge, but maybe we should take note of this assessment by The Economist: "Across the world, many cities are likely to lose inhabitants faster than buildings. To plan for shrinkage is to admit that people will not come back, which sounds like an admission of failure.
"But it may be a greater failure to seek fruitlessly to hold on to the past. Cities rise and fall, sometimes several times, changing shape as they go. It is part of their magic."
Dave Scoullar is a keen tramper, conservationist and member of the Te Araroa Whanganui Trust.
