Lifting all barriers to urban growth in America could add the equivalent of Canada’s GDP to US GDP

Lifting all the barriers to urban growth in America could raise the country’s GDP by between 6.5% and 13.5%, or by about $1 trillion-2 trillion. It is difficult to think of many other policies that would yield anything like that. The Economist magazine provides the details.

Land is really not scarce but artificial scarcity drives up prices

Buy land, advised Mark Twain; they’re not making it any more. In fact, land is not really scarce: the entire population of America could fit into Texas with more than an acre for each household to enjoy. What drives prices skyward is a collision between rampant demand and limited supply in the great metropolises like London, Mumbai and New York. In the past ten years real prices in Hong Kong have risen by 150%. Residential property in Mayfair, in central London, can go for as much as £55,000 ($82,000) per square metre. A square mile of Manhattan residential property costs $16.5 billion.

Even in these great cities the scarcity is artificial. Regulatory limits on the height and density of buildings constrain supply and inflate prices. A recent analysis by academics at the London School of Economics estimates that land-use regulations in the West End of London inflate the price of office space by about 800%; in Milan and Paris the rules push up prices by around 300%. Most of the enormous value captured by landowners exists because it is well-nigh impossible to build new offices to compete those profits away.

San Francisco could squeeze in twice as many and remain half as dense as Manhattan. This would create vast economic opportunity and could double the GDP in the big US cities.

Home ownership is not especially egalitarian. Many households are priced out of more vibrant places. It is no coincidence that the home-ownership rate in the metropolitan area of downtrodden Detroit, at 71%, is well above the 55% in booming San Francisco. You do not need to build a forest of skyscrapers for a lot more people to make their home in big cities. San Francisco could squeeze in twice as many and remain half as dense as Manhattan.

Property wrongs

Zoning codes were conceived as a way to balance the social good of a growing, productive city and the private costs that growth sometimes imposes. But land-use rules have evolved into something more pernicious: a mechanism through which landowners are handed both unwarranted windfalls and the means to prevent others from exercising control over their property. Even small steps to restore a healthier balance between private and public good would yield handsome returns. Policymakers should focus on two things.

First, they should ensure that city-planning decisions are made from the top down. When decisions are taken at local level, land-use rules tend to be stricter. Individual districts receive fewer of the benefits of a larger metropolitan population (jobs and taxes) than their costs (blocked views and congested streets). Moving housing-supply decisions to city level should mean that due weight is put on the benefits of growth. Any restrictions on building won by one district should be offset by increases elsewhere, so the city as a whole keeps to its development budget.

Second, governments should impose higher taxes on the value of land. In most rich countries, land-value taxes account for a small share of total revenues. Land taxes are efficient. They are difficult to dodge; you cannot stuff land into a bank-vault in Luxembourg. Whereas a high tax on property can discourage investment, a high tax on land creates an incentive to develop unused sites. Land-value taxes can also help cater for newcomers. New infrastructure raises the value of nearby land, automatically feeding through into revenues—which helps to pay for the improvements.