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Documentation > Miscellaneous Energy > Miscellaneous > Urbanization : a couple of figures on the french situation, and a little prolongation of trends

Urbanizing France : how long before our country is a single city ?

mars 2000 - translated in may 2004 (at last !)

website of the author : www.manicore.com - contact the author : jean-marc@manicore.com

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From the figures describing land use in France (source IFEN), I calculated the total surface covered by buildings, roads, and artificial surfaces not built (typically gardens). I also calculated the rate of increase of these various surfaces (below, surfaces are in square km).

Année

1992

% of total

1993

% of total

1994

% of total

1995

% of total

1996

% of total

1997

% of total

Change from 1992 to 1997

By year
Artificialized land not built

13 236

2,42%

13 534

2,47%

13 936

2,54%

14 232

2,60%

14 553

2,66%

14 798

2,70%

+11,80%

+2,26%
Built land

9 424

1,72%

9 589

1,75%

9 736

1,78%

9 848

1,80%

9 955

1,82%

10 077

1,84%

+6,93%

+1,35%
Roads & parking lots

15 354

2,80%

1 5572

2,84%

15 798

2,88%

16 006

2,92%

16 246

2,96%

16 346

2,98%

+6,46%

+1,26%
Forests

144 221

26,32%

145 920

26,63%

147 211

26,86%

148 097

27,03%

148 871

27,17%

149 292

27,25%

+3,52%

+0,69%
Anual cultures

151 558

27,66%

151 990

27,74%

151 617

27,67%

151 413

27,63%

152 202

27,78%

153 115

27,94%

+1,03%

+0,20%
Rocks and water

18 373

3,35%

18 308

3,34%

18 375

3,35%

18 373

3,35%

18 393

3,36%

18 416

3,36%

+0,23%

+0,05%
Permanent cultures (fruit trees...)

13 193

2,41%

13 189

2,41%

13 080

2,39%

13 016

2,38%

12 899

2,36%

12 853

2,35%

-2,58%

-0,52%
Grasslands

116 888

21,33%

115 105

21,01%

114 107

20,82%

113 766

20,76%

112 524

20,54%

111 267

20,31%

-4,81%

-0,98%
Mountain pastures

45 038

8,22%

44 449

8,11%

44 068

8,04%

43 409

7,92%

42 951

7,84%

42 516

7,76%

-5,60%

-1,15%
Scattered trees

20 669

3,77%

20 313

3,71%

20 046

3,66%

19 810

3,62%

19 359

3,53%

19 271

3,52%

-6,76%

-1,39%
TOTAL

547 954

547 969

547 974

547 970

547 953

547 951

Of which artificialized

38 014

6,94%

38 695

7,06%

39 470

7,20%

40 086

7,32%

40 754

7,44%

41 221

7,52%

+8,44%

+1,63%

All this fits what we know : urbanized land and forests grow, while grasslands decrease. One of the driving forces of this evolution is something called peri-urbanization, which designates the process by which cities grow by increasing their suburbs.

France in 1936 : 41,5 millions inhabitants

France in 1999 : 58,5 millions inhabitants (+40%). Some urban areas have grown tenfold, while rural areas emptied.

> 1000 hab/km2 500 à 1000 hab/km2 200 à 500 hab/km2 100 à 200 hab/km2

70 à 100 hab/km2 50 à 70 hab/km2 30 à 50 hab/km2 < 30 hab/km2

One might then ask oneself the following question : if we prolongate the present trends for converting "natural" land to "artifical" land, how long does it take to have cities and roads covering 100% of the mainland France ?

If we do that exercise, that is calculating the portion of the mainland covered by cities, roads, etc, by prolongating the average anual increase for the period 1992 - 1997 (that is 1,63% per year), we get the following curve :

 

Fraction of the mainland urbanized depending on the number of years after 1998.

We see above that a prolongation of the present growth rate means that mainland France has been turned to a single city in 160 years. If we assume that we cannot do without a fat 50% for agriculture and forests, then it just takes a century to urbanize the remaining 50%.

Is it legitimate to assume a growth constant in percentage and not in absolute figures ? (which would mean so many hectares per year). We must remember that a growth expressed in percentage corresponds to the case when the yearly increase is proportional to the existing value. If the increase results from peri-urbanization, assuming that the increase (at the border of the cities) is proportionnal to the size of the city is not totally stupid.

Still, the above calculation has no predictive value, of course ! In particular, when there is an upper limit to something (which is the case here : it is not possible to go over 100% of the mainland !), the general evolution never resembles the above curve, but has rather a "S-shaped" aspect, like the curve below.

 

General aspect of processes starting from zero and limited by an upper value (the horizontal axis represents time).

This being said, this little calcculation gives a rough idea of the speed at which we are currently modifying land use in France, and underlines the fact that this is absolutely not "sustainable". To be "sustainable" an evolution must not meet its limit before a century !

Let's recall that land is a limited (and not renewable !) resource, even if we can change land-use.

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