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 , 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

III. A Simple Model 1. 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×T Where 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 G 0, and its value n years later be G n, then G n ＝ G 0 (1 ＋ g) n (4) where g — GDP increase rate. The original value of environmental load per unit GDP is assumed to be T 0, and its value n years later — T n, the relationship between them will be T n =T 0 (1 － t) n (5) where t — decrease rate of environmental load per unit GDP.

Substituting Eq.(4) and Eq.(5) into it, we get I n =G 0 T 0 (1 ＋ g － t － gt) n (6) Define: t k =g / 1 ＋ g (8) Then If t ＝ t k,environmental load will keep constant; if t ＜ t k,environmental load will increase year by year; If t ＞ t k,environmental load will decrease year by year;

IV. Examples on national level 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%, t k =3.85%, but t=8%>t k, 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 to 7929, kgoe/a. So t>t k 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 t k, 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

4) Reminder: I / P ＝ A × T Tab. 2 The energy use per thousand US dollars (T) for several countries, kgoe/$10 3

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. 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

1) t<t k 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).

VI. Simulating the Environmental Load of P. R. China

In the year 2001, China ’ s gross domestic product was equal to G 0 = × 10 8 yuan [13], and energy use I 0 =13.2 × 10 8 tce [14]. Thus, energy use per unit GDP is equal to T 0 = I 0 / G 0 = tce/10 4 yuan

VII Simulation of CO 2 Emission of P. R. China

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 t k — 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.