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

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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

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Population growth of differ-tier cities in U.S.

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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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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