That Sinking Feeling: Megacities in Decline

Well, not really in decline in the way you’re thinking. Megacities, defined by the United Nations as areas with urban populations in excess of 5 million persons (think Tokyo, New York City, Mumbai), are slowly sinking into the earth – according to research from the Netherlands (and reported by the BBC). Coupled with raising sea levels due to climate change, humanity’s most densely packed population centers at risk of longer and deeper floods.

Sea Level Rise, City Subsidence (via BBC)

Land or the ground sinks into the Earth’s crust naturally, as any geographer will tell you. One method is tectonic plate movement. Depending on the plate, one may be subsumed under another with one being pushed upwards and the other being pushed under. These geologic processes also cause earthquakes and volcanic activity (see: the Pacific Ring of Fire). As the BBC article points out, this geologic activity may be responsible for about 1 mm of subsidence a year. According to the research, a longitudinal study using radar imagery (measuring elevation), concludes that human activity – particularly groundwater extraction – is the primary culprit for city subsidence.

In most cases, a city’s drinking water supply is sourced from local groundwater. As this water is extracted from underground aquifers, one would assume that heavier buildings and infrastructure would press down upon, and compact, the underlying soils. Of course, the relative amount of compaction would be dependent on the local soil (sand, clay, silt, and other factors). While some cities have reduced, if not almost wholly eliminated, municipal subsidence (the article mentions Tokyo and Venice) by halting groundwater extraction – this option isn’t a realistic solution for coastal megacities in less economically advanced countries (Dhaka, Lagos, Jakarta). In these and other “smaller” cities (between 1 and 5 million persons) municipal budgets are already strained coping with a vast informal housing sector (read: slums and shantytowns), a stagnant infrastructure, and poor administration. Adding a requirement for an entirely new source of drinking water for an entire city would be prohibitively expensive.

However, given rising sea levels, municipal subsidence, some 75% of humanity lives on the coast (but not necessarily in a city), and about half of humanity lives in cities (not necessarily on a coast) – we can easily see the scale of the problem. Fortunately, the problem is somewhat long-term, city subsidence and sea level rise occurs at rates of millimeters a year. However, though the number is small the results are disproportionately large. A National Geographic article, published Sep 2013, cited a OSCE report stating that a 20-inch sea level rise would leave 150 million people and $35 trillion dollars (about 9% of global GDP) at risk of coastal flooding. A city sinking 20-inches, an easy analogy, would take 40 years at 5 mm a year.

Of course, this timeline would compress markedly if cities are to contend with both rising sea levels and their own sinking. The timeline is likely to further compress if urban population growth rates remain high as new residents also demand access to water.

Even more long-term, Z Geography wonders if the growth of megacities will lead to their own decline. Could this natural hazard (coastal flooding) combine with other human-made hazards in cities (violent conflict, poverty) and lead to a period of deurbanization in the next 50, or 100, years? One could argue “yes”, in the true spirit of Malthus, but we shall watch for technological and economic innovation – perhaps a cheaper way to reduce our dependence on groundwater?

Urbanization in China

Recently, my favorite remote sensing site (Earth Snapshot) released the below image taken at night over eastern, coastal China (People’s Republic of). Its a striking visualization of the extent of urbanization in the PRC, not to mention the almost continual stretch of development along one side of the island of Taiwan, which hosts the Republic of China. The upper (northern) urban areas are Shanghai and Hangzhou, the former being the largest city in China. The southern area is the former British dependency of Hong Kong.

Nighttime Lights over eastern Asia (via EOsnap)

Despite the size of the PRC’s urban areas, only a little more than half of the country’s 1.3 billion persons resides in cities, compared to rural areas, based on 2013 estimates from the U.S. Census Bureau.

Bloomberg news reported in January 2012 (based on 2011 data) that China’s population had just flipped from being primarily rural to urban. While a worthy news even in of itself, it is particularly significant considering that rural dwellers represented 81% of the population in 1979. Further, the growth in urban areas has really come since 1979 – as Bloomberg points out, the proportion of rural-urban proportion decreased about 9 percentages points between 1949 and 1979. Of course, Mao Zedong was in control of the People’s Republic of China during practically all of this time. It was he who undertook the Great Leap Forward and the Cultural Revolution, both programs emphasized the rural character of the country at the expense of the nascent urbanity.

One wonders to what extent these programs were “rewards” for the rural population’s support of Mao during the Chinese Civil War. Other academics have pointed out, that Mao’s initial communist rebellion failed because he attempted to fully replicate the Russian model in the sense that it began in the cities. After Mao’s initial failure he shifted his strategy to the countryside.

Now most mainland Chinese live in the cities, where they earn three times more than their rural counterparts, but rural incomes have grown faster than urban ones. The challenge now, as Bloomberg correctly points out, is properly managing this quickly expanding urban population. An explosion in the urban population necessarily requires a commensurate increase in the infrastructure and services that this population requires:  food, water, shelter, education, employment, and other things. While the PRC has reaped the benefits of a quickly expanding urban population (in terms of income generation for the state), it remains to be seen what will happen when the economy slows.

Places and Spaces: Filling Empty Spaces

This is the final post in a short series on the issue of “place.” Place and space are sometimes used in interchangeably, but less so recently. If you think about it, you can reason why. “Place” has connotations of significance to the people who use it. “Space” could have these same connotations, but the word itself implies a sort of nothingness: think outer space. Through this short series of posts, I’ll be emphasizing the importance of examining your own world in terms of its places and spaces. This has more implications than just academic, if you do commit to understanding places and spaces you can begin to change them and make them “better.” For an introduction to this series, click here.

In this post, we explore efforts to make spaces into places. As we saw in the second post (here) a consequence of our (the “West’s”) obsession/dependence upon automobile-borne transportation, particularly private forms, has been literal and figurative dead spaces. Spaces where nothing grows and no one goes.

One hallmark of humanity is that we do try to improve our surroundings, not only functionally but aesthetically. Of course, aesthetically pleasing places are usually tied to affluence (thanks politics!). The pictures below were all taken in Arlington, Virginia and highlight the in-between nature between places and spaces. I don’t have a clever word to describe these spots. Splace? There we go, splace. It sounds kind of silly and amorphous, which is what these splaces are.

Art under an Underpass, Arlington, VA (via ME!)

Art under an Underpass, Arlington, VA (via ME!)

Colored Columns, Arlington, VA (via ME!)

Colored Columns, Arlington, VA (via ME!)

The two pictures above are…interesting. The first depicts art underneath a freeway overpass. I don’t know how I would feel about my artwork being relegated to an area under an underpass, countless motorists passing over your work, 99% not realizing that they’re speeding over it. As a pedestrian I suppose I appreciate the sentiment, this is on the way to the grocery store for me, but do I ever stop to admire this? No. And it’s not la gallery where the work is rotated occasionally. And if it is than I’m also making my point. I don’t stop here, I’m underneath an overpass. The second just makes me laugh whenever I run by it. Colored columns. Recently, a friend observed that it this was affluent-place behavior. I have to agree, spending money to paint overpass-support columns. Incidentally, these dead spaces end up housing the very things that birth their existence – automobiles.

An...underpark? Arlington, VA (via ME!)

An…underpark? Arlington, VA (via ME!)

And then there’s the picture at left. A park built under an overpass. It’s quite curious. I still don’t know if it’s a good idea. My friend and I visited this splace (since its right across from the colored columns above) and didn’t quite know what to make of it. I certainly doesn’t help that the building outside the shot produces a loudish buzzing. No grass. No trees. Nothing, except some benches, a trashcan, and a lot of rocks. I wouldn’t spend time here, but there are quite a few cigarette butts lying about so I guess that’s one use for this splace.

Despite these futile attempts at creating a livable place, there are some notable mentions.

Park Row, Arlington, VA (via ME!)

Park Row, Arlington, VA (via ME!)

Roadside Gym, Arlington, VA (via ME!)

Roadside Gym, Arlington, VA (via ME!)

The two photos above show some notable splaces. On the left is a row of benches and greenspace just outside a very tall hotel. While a wonderful idea, benches and greenspace, rather than have the benches face the green grass they face…a blank building wall. The roadside gym is actually a great idea. There is an on-ramp in this shot but it’s wonderfully obscured in most places by trees. There’s a basketball hoop, a running trail, and outdoor exercise equipment making it a place for fitness. When I’m in the area I routinely see people at the basketball hoops or sitting on the benches, relaxing.

There are some lessons to be drawn from these photos and I have been harping on these concepts throughout the series. The importance of green space. We’ve spent most of our evolutionary history outdoors, in and among greenery. I know (but can’t cite a reference) that some studies of urban workers (in Finland) found that the happiest and most stress free took frequent vacations or lunch breaks to “natural areas”, whether further in a “rural area” or in a park. Similarly, others kept pictures and paintings of greenery in their cubicles – to remind them of life outside a building. Green space needs good lighting. As we’ve spent most of our time outdoors, we’ve invariably spent it in the sun (we get vitamins from that star too). Freeway underpasses can never, ever be a place for humans. There’s no light and no green.

Places and Spaces: No Place (in particular)

This is the second in a short series of posts on the issue of “place.” Place and space are sometimes used in interchangeably, but less so recently. If you think about it, you can reason why. “Place” has connotations of significance to the people who use it. “Space” could have these same connotations, but the word itself implies a sort of nothingness: think outer space. Through this short series of posts, I’ll be emphasizing the importance of examining your own world in terms of its places and spaces. This has more implications than just academic, if you do commit to understanding places and spaces you can begin to change them and make them “better.” For an introduction to this series, click here.

This post presents some of the legacy of “modernism”, specifically the gift of the no place. By way of introduction let’s discuss “modernity”, in terms of discussing the humanity’s impact on the physical environment you would probably think of two things: tall buildings and highways. While tall buildings can be places – of work, residence, or fun – highways are most definitely not places. Highways are space we utilize to get from place to another, very few people are enamored with them. Quite the opposite nowadays, not least because they are a place of extreme danger for anyone not in a car. I sometimes wonder how many roadside memorials exist (in the United States) for children hit by motorists?

Ah – the car. For a fantastic discussion of this machine-god see James Howard Kunstler’s The Geography of Nowhere (1994).

Highways, in all their concrete and steel glory, are a monument to the car. And while they exist solely to make automobile traffic somewhat economical (to say nothing of the time-wasted at this point), it wantonly destroys the rest of the landscape. In particular, where the highway is, human beings – pedestrians, bicyclists, skateboarders, and skaters – are not. Unless they’re crazy, it takes a man or woman of nerve to share the road with a 3,500 pound beast hurtling at 60+ mph. I invite a physicist (or mathematician) to enlighten us on the amount of force such a mass would have when hitting a standing pedestrian.

Side note: I was hit by a taxi cab once, so this does practical applications.

The three pictures below I took during one of my runs in Arlington, VA. This is the “natural” lighting (that is 0 F-stops, no compensation in shutter speed or aperture to increase available light). They were taken under the Jefferson Davis Highway and George Washington Parkway bridges that span Four Mile Run (the body of water).

Photo by Four Mile Run (via ME!)

Photo by Four Mile Run (via ME!)


Photo by Four Mile Run (via ME!)

Photo by Four Mile Run (via ME!)

Photo before Bridge (via ME!)

Photo before Bridge (via ME!)

There are two comparisons to be drawn from these photos. First, the importance of light. When I’m running under these bridges I run faster, always, not just because its cooler but because its dark and dank. I don’t want to be here. Second, things that grow. In the third photo, there are a pile of rocks in the corner. In the first two photos there is a veritable explosion of greenery (thanks to the available light).

The area under these bridges, human-made structures purpose-built to facilitate automobile traffic (ONLY), is empty, wasted space. There is no light and nothing grows here. More often than not this space smells worse than the water treatment plant up the trail.

To be somewhat even-handed, these spaces aren’t a total waste. I often see people fishing under these bridges. And some pigeons roost here as well.