Crossing “Environmental Mountain”—On the Increase and Decrease of Environment Load in the Process of Economic Growth

Lu Zhongwu(陸鐘武 ), Mao Jiansu(SEPA Key Laboratory for Industrial Ecology, Northeastern University, Shenyang 110004, China)

I. Abstract

1.The curve of environmental load in the process of economic growth in developed countries was likened to "environmental mountain".

2.The formulas of the relationship between environmental load and GDP were derived, in which there are 2 key variables: g─growth rate of GDP; t─decreasing rate of environmental load per unit GDP.

3.Taking several countries and provinces in China as examples, the relationships between economic growth and energy consumption were studied.

4.The environmental load of China in the years 2005, 2010 and 2020 were anticipated under different assumptions, and further discussion was given in terms of energy consumption and CO2 emission.

II. Stylized Facts and Some

Conjectures Fig. 1 The relationship between resource use and

the state of development

Immediate

action

Longer-term vision

now （less developed）

(a)

State of development

Res

ourc

e us

e Industrial revolution

now

State of development

(b)

Res

ourc

e us

e

now （more developed）

III. A Simple Model1. Definitions: I=P×A×T=G×T (The IPAT equation)--------- (1)where I —environmental load, including resource uses and

waste; P —population; A —per capita gross domestic product; T —environmental load per unit gross domestic

product.G —gross domestic product, GDP.Dividing both sides of Eq.(1) by P, we get I / P=A×TWhere I/P is per capita environmental load.

2.Assumptions and the Model:

Assume:Exponential increase of G and exponential decrease of T .

Let the original value of GDP be G0, and its value n years later be Gn, then

Gn ＝ G0(1 ＋ g)n------------------------------- (4)where g — GDP increase rate.The original value of environmental load per unit GDP is assumed to be T0, and its value n years later — Tn, the relationship between them will be

Tn=T0(1 － t)n--------------------------------- (5)where t — decrease rate of environmental load per unit GDP.

Substituting Eq.(4) and Eq.(5) into it, we get In=G0T0(1 ＋ g － t － gt)n --------- (6)Define: tk=g / 1 ＋ g------------------------- (8)Then If t ＝ tk ,environmental load will keep constant;if t ＜ tk ,environmental load will increase year

by year;If t ＞ tk ,environmental load will decrease year

by year;

Tab.1 The calculated values of tk according to tk=g/1+g

g 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15

tk 0.0099 0.0196 0.0291 0.0385 0.0476 0.0566 0.0654 0.0741 0.0826 0.0909 0.0991 0.1071 0.1150 0.1228 0.1304

IV. Examples on national level

Per capita GNP, U.S.dollar

Per

cap

ita

ener

gy u

se, k

goe/

a

0

2000

4000

6000

8000

10000

12000

0 10000 20000 30000 40000

USA

Canada

Norway

Sweden

Holland

Japan

South Korea

Mexico

P. R. China

Egypt

France

Britain

Fig. 2 The curves of per capita energy use- per capita GNP for several countries

In the Figure, 3 points denote the per capita energy use （ I / P ） in the years 1980, 1990 and 1999, respectively.

1) In Norway,g=4%, tk=3.85%, but t=8%>tk,

therefore I/P decreased from 9083 to 5965 kilogram oil-equivalent per year (kgoe/a).

In Canada,g=1%, tk=0.99%, but t=3%>tk, therefore the value of I/P decreased from 10009 to 7929, kgoe/a.

So t>tk is the common feature of Canada,

Norway,Sweden and Holland in the 90’s of the 20th century.

2) For other developed countries, the value of t of each of them approaches or equals to the value of its tk, so per capita energy use in these countries slightly increased or even kept constant.

3) For developing countries, per capita energy uses were increasing. For instance, in South Korea, the decrease rate of energy use per unit GNP was 7%, but the increase rate of per capita GNP — 14%, therefore per capita energy use increased from 1087 to 1898, kgoe/a, in the period of 1980-1999.

4) Reminder: I / P ＝ A × T

Tab. 2 The energy use per thousand US dollars (T) for several countries, kgoe/$103

year Japan Norway Holland USA Canada Mexico South Korea China

1980 300 363.6 400.5 698 774.4 711 715 1452

1990 140 392.8 295.8 359 489.0 522 351 1616

1999 114 127.7 187.7 239 357.3 304 434.5 1033

5)The history of economic growth and energy use in USA, P. R. China and Japan in the last half-century is shown in Fig.3.

0

5

10

15

20

25

0 2000 4000 6000 8000

USA

P. R. China

GDP, billion U.S. dollars

Com

mer

cial

ene

rgy

cons

umpt

ion,

108

toe

Japan

1970

1980

1990

1996 1990

1996

1990

1980

1980

1996

Fig. 3 The curves of commercial energy consumption- GDP for USA, P. R. China and Japan

V. Examples on provincial level Fig. 4 The curves of per capita energy use- per capita GDP for several provinces and cities of China

0

500

1000

1500

2000

2500

0 1000 2000 3000 4000 5000

Shanghai

Beijing

Tianjin

Liaoning

Zhejiang

Guangdong

Xinjiang

Gansu

whole nation

Shanxi

Per capita GDP, U.S. dollar

Per

cap

ita

ener

gy u

se, k

goe/

a

1) t<tk is the common feature of all provinces and cities, hence per capita energy use in these provinces and cities increased.

In Zhejiang province, energy use per unit

GDP decreased approximately 5% each year, but per capita GDP increased approximately 14%, so per capita energy use raised from 411 to 907 kgoe/a.

2) The energy use per unit GDP of various provinces and cities differ greatly from each other (see Tab.3).

Tab.3 Energy use per unit GDP of several provinces and cities in P.R.

China, kgoe/$103

year Guangdong Shanghai Zhejiang Liaoning Xinjiang Gansu

1980 1364 1257 1529 3655 4533 3760

1990 825 1311 926 2369 2452 2843

2000 491 550 557 1203 1337 1866

VI. Simulating the Environmental Load of P. R.

China

Tab.4 The simulated values of G,I and T of China in 2005, 2010 and 2020

year GDP(G) environmental

load(I) environmental load per

unit GDP(T) 2001 G0 I0 T0

g =0.07，t =0.00 2005 1.311 G0 1.311 I0 T0 2010 1.838 G0 1.838 I0 T0 2020 3.316 G0 3.316 I0 T0

g=0.07，t =0.04 2005 1.311 G0 1.113 I0 0.849 T0 2010 1.838 G0 1.273 I0 0.693 T0 2020 3.316 G0 1.665 I0 0.460 T0

g=0.07，t = tk =0.0654 2005 1.311 G0 I0 0.763 T0 2010 1.838 G0 I0 0.554 T0 2020 3.316 G0 I0 0.277 T0

In the year 2001, China’s gross domestic product was equal to G0=95933.3×108 yuan[13], and energy use

I0=13.2×108 tce[14]. Thus, energy use per unit GDP is

equal to T0= I0 / G0 = 1.376 tce/104 yuan

Tab. 5 The simulated values of GDP, energy use, energy use per unit GDP of China in 2005, 2010 and 2020

year GDP 108yuan energy use 104tce

energy use per unit GDP tce/104yuan

2001 95933.3 132000 1.376

07.0g ， 00.0t

2005 125749.0 173025.1 1.376

2010 176369.5 242676.6 1.376

2020 346945.4 477381.6 1.376

07.0g ， 04.0t

2005 125749.0 146958.3 1.169

2010 176369.5 168061.8 0.953

2020 346945.4 219795.7 0.634

07.0g ， t=kt=0.0654

2005 125749.0 132000 1.050

2010 176369.5 132000 0.749

2020 346945.4 132000 0.381

VII Simulation of CO2 Emission of P. R. China

Tab. 6 Reduced emission volume of CO2

before and after emission reducing measures

year GDP 108yuan

CO2 per unit GDP 104 tCO2/108yuan CO2 volume

(before)104 tCO2 CO2 volume (after)104 tCO2

CO2 reduced emission volume 104 tCO2

2001 95933.3 1.04 ×10-5 P0 P0 － － g=0.07，t=0.00

2005 125749.0 1.04 ×10-5 P0 1.311 P0 1.272 P0 0.039 P0 2010 176369.5 1.04 ×10-5 P0 1.838 P0 1.701 P0 0.137 P0 2020 346945.4 1.04 ×10-5 P0 3.617 P0 3.256 P0 0.361 P0

g=0.07，t=0.04 2005 125749.0 0.88 ×10-5 P0 1.113 P0 1.078 P0 0.035 P0 2010 176369.5 0.72 ×10-5 P0 1.273 P0 1.188 P0 0.085 P0 2020 346945.4 0.48 ×10-5 P0 1.665 P0 1.516 P0 0.149 P0

g=0.07，t=0.0654 2005 125749.0 0.79 ×10-5 P0 P0 0.972 P0 0.028 P0 2010 176369.5 0.57 ×10-5 P0 P0 0.939 P0 0.061 P0 2020 346945.4 0.29 ×10-5 P0 P0 0.921 P0 0.079 P0

VIII. Conclusion

1.Crossing “environmental mountain” might illustrate the basic characteristic of the new way of industrialization in the respect of the relationship between environment and development.

2.The decision to cross “environmental mountain” should be made promptly and opportunely.

3.The value of t — the decrease rate of environmental load per unit GDP should be raised by every possible means, so as to make it near, equal to, or even larger than the value of tk — the critical value of t.

4.The long-term plan of development and environment should be worked out in line with local conditions; the target values of g, t, T, I for each stage of the plan should be determined scientifically.