University of Tokyo's forecast for Tokyo

In looking for future forecasts from Japan, I ran across Tokyo University's Center for Sustainable Urban Regeneration, "the research center that integrates the four specific fields of urban planning, architecture, civil engineering and environmental engineering with the participation of over a hundred researchers of the university." While most of the papers are surprisingly missing (broken links), I found one relevant paper titled "Tokyo 2050, Sustainable Regeneration of Tokyo Scenario." (note: the document is in Japanese so I'm translating everything I mention here) The document was a mid project report published in 2005, and covered the first 2 steps of their 5 step program:

1. Projecting future population statistics from current trends.
2. Identifying the problems that may arise from such projections.
3. Developing different political scenarios to avoid those problems.
4. Forecasting the futures from each scenario.
5. Taking action with informed consent.

I presume the rest of the project is complete or near complete but I could not find them anywhere online. It might be worth a follow up if this is one of the avenues we want to look deeper into.

A lot of the findings were similar to the earlier UN reports I posted, but this one goes into a finer granularity and focuses more on the specifics of Tokyo. It also points out future issues that aren't entirely obvious from the projected numbers.

Findings:

"Tokyo's suburbanization and growth is coming to an end, and the 21st century will focus on urban redevelopment and maturation. Population decline, aging, and smaller households dictate the reorganization of urban habitation and employment."

Something I was completely unaware of: From the mid 80s to the end of the bubble economy in 93 when land prices in central Tokyo was exorbitantly high, population in the central districts of Tokyo decreased significantly as homes became too expensive to own in those areas.

(Light blue: Central 3 districts, Red: Inner 5 districts, Yellow: Surrounding 15 districts, all within Tokyo Municipality)

Following the economic collapse of Japan, the population in central Tokyo returned slowly which is generally called Tokyo Center Revival (along with the "lost decade" for all of Japan, NYT has a good historical perspective on this).

As expected, population decline in Tokyo will start in 2015, and the area farthest from city center will be affected first:

However, the population change is not as uniform as see above.
This shows the population change in districts of Tokyo Prefecture (subset of Tokyo Urban Area) from 1995 to 2000 (Central Tokyo is at the far east, slightly south of center). Deep blue shows sharp decline in population while red shows sharp increase in population. Beside the farthest districts losing population, no other trends are obvious. What's more interesting is that some blue areas are surrounded immediately by red areas (explanation of which is not entirely obvious from this map).

As aging occurs and family size decreases (shrinking are households with children and increasing are single and couple households), residential types are changing too. Disappearing are low-rise apartment complexes and appearing are high-rise condos. Houses aren't disappearing but aren't increasing either. Tokyo Center Revival was supported by new high-rise condos catering to smaller family sizes.

(Note: House sharing, i.e. roommates, are very rare in Japan as people choose to live in tiny study apartments rather than share facilities with others. Also, while land is considered valuable in Japan, buildings are not. Peering into real estate agency windows, you'll notice that old houses will actually decrease the value of the land on which it stands).

Another change driven by aging is the motivation for urban movements. Around 2030, personal trips for males are projected to surpass commuting. That compounded with population decline should significantly decrease the temporal traffic jams and transit congestion. If anything, the issue may shift to how better support the extensive transit network with less people (especially less people in the working age).


(Left chart for males, right for females, x for personal, triangle for business related trips, square for commuting to school, dot for commuting to work)

Future Issues for Tokyo

In the age of urban growth, the central focus was on the quantity of the "receiving plate" (like many of the developing world megacities, Tokyo's population spike in the 50s and 60s were supported by migrants) However, now that growth is nearing an end, the focus will shift to the quality of the "receiving plate."

Decreasing population will relax the dependencies on many of the existing urban infrastructure, but lower demand may create issues in supporting some of those high maintenance infrastructure.

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The document goes into much more detail and discusses many other issues that I didn't include. If anything, it's a stark contrast from the techno-centric forecast on Underground Automated Highways and much more of a demographic-centric projection into the future. I still haven't found a forecast that convincingly combines these two factors, which the future of transportation in megacities must consider.