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Changes in Sealing Surface in China
Minghong TAN Xiubin LI
Institute of Geographical Sciences and Natural Resources Research The Chinese Academy of Sciences
Contents • Built-up area growth
– Spatial variation – Variation across different-tier cities – Expansion of different types of urban land uses
• Urban built-up area expansion and arable land loss • Fast or slow? Compared with rapid growth of urban
population • Future tendency
Built-up area expansion
1. 276 cities higher than county level
2. 374 cities at the county level
3. 1474 county town
4. Many towns and villages
The largest 11 regions of urban agglomeration
Built-up area expansion • The total areas were about 44 thousand km2 in 2010
during the past 10 years (Statistics data).
The rates of built-up area increase
Built-up area growth（km2）of 145 cities in China in the 1990s
< 35
35 -70
> 70
600km
a)
73: East China
51: Central China
21: West China
Built-up area expansion: Spatial variation
Changes of urban built-up areas of different regions in China, 1990-2000
Increased by /% New areas /km2
The East 44.0 2661 Central 17.8 512 The West 33.1 368 Average 39.8 -
Land area based on remote sensing
In the 1990s, total built-up areas of 145 cities as a whole, expanded by 3500 km2, of which the cities of the East accounted for 75%, the Central15% and the West 10%.
Rates of built-up area expansion of different-tier cities in the 1990s
City tiers Urban land increase(%)
Large city 48.1
Medium city 34.4
Small city 27.9
Growth of different urban land use types
• Residential areas are highly crowded
• Industrial land, various development zones, and the land use for government’s departments: low efficiency
• Increases in rural residential areas
Residential areas in Beijing: near to Olympic Park
18 storeys 324 households
6 storeys 90 households
About 900 households in total
Tokyo
About 100 households
Brussels
Less than 80 households
Industrial land, development zones
A part of Yizhuang development zone at the nation level
Increases in rural residential areas, 1974-2007
Land area based on remote sensing Urban land in 1990
New urban land from arable land
New urban land from non-arable land
• Most of new urban land was converted from arable land. The shares in the East, the Middle and the West, were 69.0% and 72.0%, 80.9%, respectively.
Urban built-up area expansion and arable land loss
Shares of new urban areas converted from arable land in different-tier cities
• In Jingjintang region, the share for small cities was highest and reached 81.0%, followed by medium cities (73.9%) and large cities (65.4%).
Urban built-up area expansion and arable land loss
Classification of food yields (kg/hm2) of urban district of 145 cities in 1995. Data come from ref. [17]; the China’s average of food yield was about 6700 kg/hm2 in 1995.
The yield of arable land converted to urban built-up areas is 1.47 times of the average level of the whole country
Dispute: Fast or slow?
• Increase in urban built-up area is one of the hottest topic in China
• Most authors think that the rate of urban built-up areas increase too quickly.
Dispute: Fast or slow?
• 1990-2000, the surfaces of 120 cities grew on average more than twice as fast as their populations. These rates are unlikely to change.
• Urban density decreased by 2.01% per year
Shlomo Angel (2012), gathered historical and census data from hundreds of cities. Land data is from digitized pictures. http://www.economist.com/node/21557313
Lower than the world average level
• 2000-2009, urban built-up areas incresed from 21.8 thousand km2 to 40.5 thousand km2, based on the data from remote sensing data, interpreted by The Institute of Remote Sensing and Digital Earth (RADI), (CAS）.
• For the cities with population over 0.5 million, urban built-up areas increased by 7.01%, while urban population increase by 5.83%. Urban density decreased by 1.11% per year, which was much lower than the world average level.
Decrease in urban population density: Reasons
Income rising Family size decreasing Car use …
Decrease in population density
0.00.51.01.52.02.53.03.54.04.55.0
1953 1964 1982 1990 2000 2010
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Urban population density is still very high in China
Area Cases Population
(106) Population/k
m2 Density /
China
High Income World Europe 63 107 3,050 29 United States 71 140 1,150 11 Australia 5 10.4 1,450 14 Japan 16 72 4,800 45 China (Hong Kong & Macao) 1 6.5 29,400 279 Total/Average 192 408 3,100 29
Middle and low income world Europe Except Russia 29 41.2 4,750 45 China 102 141 10,550 100 India 61 122 15,700 149 Russia 36 42.1 5,250 50 Africa 75 128 8,200 78 South & Central America 94 183 6,650 63 Total/Average 492 845 9,200 87
http://www.demographia.com/db-intlua-area2000.htm
684: The High Income World: US$17,500+ GDP (PIB) Purchasing Power Parity per Capita 2003
Geographical summary; Urban areas over 500,000 (Threshold)
Population density is still very high: 135 cities
135 cities and their population densities (1000 persons /km2) in China in 2000
The black line goes along Huai River and Qinling Mountanin, which divide China into two regions, namely, South China and North China
Future Tedency
Future tendency
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U.S.ChinaChina: projection data
100 Years
Population growth of differ-tier cities in U.S.
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年份
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A: Ranks between 1-10 B: between 11-50； C: between 51-100; D: between 101-214 The largest city is listed as the first rank.
Population growth at differ city ranks, 1900-2000
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1 25 49 73 97 121 145 169 193 217 241 265 289 313
Tim
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City rank
1970-2000年
1900-1970年 The Unite States
1900-1970 population in the large cities increased more quikly, during the process of rapid urbanization
Lage cities increases: ‘out of control’ in China
• Urban master planning: in 2020, Beijing popualation should be less than 20 million. However, in 2011, population was 20.13 million.
• Urban master planning: in 2020, Shanghai popualation should be about 20 million. However, in 2011, population was 23.47 million.
For a large country with a population more than 1.3 billion, how many peopeles will the largest city have??
Urban land will expand quickly in the future, especially for large cities
Thanks
