The US has become a nation of suburbs. But will it stay that way?

The American dream in Highland, California. Image: Getty.

Since 1970, more Americans have lived in the suburbs than central cities. In 2010, suburbanites outnumbered city and rural dwellers combined for the first time. Americans live in a suburban nation.

Despite several concerted efforts by city governments to lure residents, suburbanisation continues largely unabated. Census figures from earlier this year show that suburbs of warm climate “Sun Belt” cities in the South and West continue to grow, while cities in the cold climate “Snow Belt” of the Midwest and Northeast decline.

Smaller metropolitan areas with fewer than 500,000 people have also grown, related to an improving economy and job creation in smaller urban centers. This ongoing shift towards the suburbs has significant environmental repercussions.

Since cities and suburbs are home for 8 of every 10 Americans, views of the country are often distorted. Most travel occurs within or between cities. Although rural areas have more than three times the miles of roadways as urban areas, more than two-thirds of the 3trn miles that vehicles travel each year in the U.S. are in urban and suburban areas.

Jobs, too, are overwhelmingly centered around cities. Less than 2 per cent of the American labor force is employed in agriculture.

Many of my students are surprised that the land area occupied by cities is only 3 per cent of the nation’s territory. However, they are correct in that cities have an outsized impact on the economy. In 2016, metropolitan areas contributed $16.8trn to the nation’s gross domestic product, more than 90 per cent of the country’s economy.

With this economic activity comes a high use of natural resources and concentrated pollution production. Although density can be more efficient when it comes to energy use, the sheer number of urban dwellers means that cities, despite a small physical footprint, have a big energy and pollution footprint.

Rising suburbanisation undermines some of the energy efficiency gained by high density living in urban cores. Manhattan has lower per capita greenhouse gas emissions than the suburbs of New York, thanks to factors like apartment living, high costs of car ownership and extensive public transit. Of course, not everyone can afford to live in Manhattan even if they want to. Low-density suburbs are an affordable alternative.

Even so, suburban life can look less desirable. As the U.S. population ages, elderly people may end up “stranded in the suburbs,” far from adequate public transit and unable or unwilling to drive. At my urban university, a mixed use retirement facility was sold out before ground was broken. In the U.S., there are more than 100 university-based retirement communities and the number is growing.


The trend toward suburban life could soon come to an end. Millennials – the generation born between 1981 and 1997 – appear to prefer urban life. They are happier in cities, especially large metropolitan areas, than older generations. The millennial population is growing fastest in metro areas in the Sun Belt and western states, and slowest in the Snow Belt. Topping the list of the fastest-growing metropolitan areas for millennials are Colorado Springs, San Antonio, Denver and Orlando.

Will millennials follow older generations to the suburbs as they marry, have children, recover from the shocks of the Great Recession and find affordable housing? The jury is still out.

Whatever happens, it’s unlikely that people will start to move out of cities and suburbs and back into rural areas. Even though increased connectivity and the internet of things will make remote work more possible than before, businesses will continue to concentrate in urban cores, because they profit from being close to one another. (Futurists once thought the telephone would make crowded cities unnecessary.)

I believe that it’s likely the U.S. will remain a nation of suburbs for some time to come. That will pose a continuing environmental challenge. But it will also bring a new set of opportunities for millennials, who are predicted to overtake baby boomers by next year as the largest generation in the country. How will that generation remake the suburbs to suit their needs and desires without exacerbating current environmental challenges? The answer has profound implications for the nature of cities and urban life in the U.S.

The Conversation

Christopher Boone, Dean and Professor of Sustainability, Arizona State University.

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The IPPC report on the melting ice caps makes for terrifying reading

A Greeland iceberg, 2007. Image: Getty.

Earlier this year, the Intergovernmental Panel on Climate Change (IPCC) – the UN body responsible for communicating the science of climate breakdown – released its long-awaited Special Report on the Ocean and Cryosphere in a Changing Climate.

Based on almost 7,000 peer-reviewed research articles, the report is a cutting-edge crash course in how human-caused climate breakdown is changing our ice and oceans and what it means for humanity and the living planet. In a nutshell, the news isn’t good.

Cryosphere in decline

Most of us rarely come into contact with the cryosphere, but it is a critical part of our climate system. The term refers to the frozen parts of our planet – the great ice sheets of Greenland and Antarctica, the icebergs that break off and drift in the oceans, the glaciers on our high mountain ranges, our winter snow, the ice on lakes and the polar oceans, and the frozen ground in much of the Arctic landscape called permafrost.

The cryosphere is shrinking. Snow cover is reducing, glaciers and ice sheets are melting and permafrost is thawing. We’ve known this for most of my 25-year career, but the report highlights that melting is accelerating, with potentially disastrous consequences for humanity and marine and high mountain ecosystems.

At the moment, we’re on track to lose more than half of all the permafrost by the end of the century. Thousands of roads and buildings sit on this frozen soil – and their foundations are slowly transitioning to mud. Permafrost also stores almost twice the amount of carbon as is present in the atmosphere. While increased plant growth may be able to offset some of the release of carbon from newly thawed soils, much will be released to the atmosphere, significantly accelerating the pace of global heating.

Sea ice is declining rapidly, and an ice-free Arctic ocean will become a regular summer occurrence as things stand. Indigenous peoples who live in the Arctic are already having to change how they hunt and travel, and some coastal communities are already planning for relocation. Populations of seals, walruses, polar bears, whales and other mammals and sea birds who depend on the ice may crash if sea ice is regularly absent. And as water in its bright-white solid form is much more effective at reflecting heat from the sun, its rapid loss is also accelerating global heating.

Glaciers are also melting. If emissions continue on their current trajectory, smaller glaciers will shrink by more than 80 per cent by the end of the century. This retreat will place increasing strain on the hundreds of millions of people globally who rely on glaciers for water, agriculture, and power. Dangerous landslides, avalanches, rockfalls and floods will become increasingly normal in mountain areas.


Rising oceans, rising problems

All this melting ice means that sea levels are rising. While seas rose globally by around 15cm during the 20th century, they’re now rising more than twice as fast –- and this rate is accelerating.

Thanks to research from myself and others, we now better understand how Antarctica and Greenland’s ice sheets interact with the oceans. As a result, the latest report has upgraded its long-term estimates for how much sea level is expected to rise. Uncertainties still remain, but we’re headed for a rise of between 60 and 110cm by 2100.

Of course, sea level isn’t static. Intense rainfall and cyclones – themselves exacerbated by climate breakdown – can cause water to surge metres above the normal level. The IPCC’s report is very clear: these extreme storm surges we used to expect once per century will now be expected every year by mid-century. In addition to rapidly curbing emissions, we must invest millions to protect at-risk coastal and low-lying areas from flooding and loss of life.

Ocean ecosystems

Up to now, the ocean has taken up more than 90 per cent of the excess heat in the global climate system. Warming to date has already reduced the mixing between water layers and, as a consequence, has reduced the supply of oxygen and nutrients for marine life. By 2100 the ocean will take up five to seven times more heat than it has done in the past 50 years if we don’t change our emissions trajectory. Marine heatwaves are also projected to be more intense, last longer and occur 50 times more often. To top it off, the ocean is becoming more acidic as it continues to absorb a proportion of the carbon dioxide we emit.

Collectively, these pressures place marine life across the globe under unprecedented threat. Some species may move to new waters, but others less able to adapt will decline or even die out. This could cause major problems for communities that depend on local seafood. As it stands, coral reefs – beautiful ecosystems that support thousands of species – will be nearly totally wiped out by the end of the century.

Between the lines

While the document makes some striking statements, it is actually relatively conservative with its conclusions – perhaps because it had to be approved by the 195 nations that ratify the IPCC’s reports. Right now, I would expect that sea level rise and ice melt will occur faster than the report predicts. Ten years ago, I might have said the opposite. But the latest science is painting an increasingly grave picture for the future of our oceans and cryosphere – particularly if we carry on with “business as usual”.

The difference between 1.5°C and 2°C of heating is especially important for the icy poles, which warm much faster than the global average. At 1.5°C of warming, the probability of an ice-free September in the Arctic ocean is one in 100. But at 2°C, we’d expect to see this happening about one-third of the time. Rising sea levels, ocean warming and acidification, melting glaciers, and permafrost also will also happen faster – and with it, the risks to humanity and the living planet increase. It’s up to us and the leaders we choose to stem the rising tide of climate and ecological breakdown.

Mark Brandon, Professor of Polar Oceanography, The Open University.

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