雙向分量迴歸模型之建構--二氧化碳與經濟發展關係再檢視

Abstract

為同時考慮不同CO2排放水準以及不同的經濟發展程度，本文針對每人每年CO2排放量進行不同程度區分的分量迴歸，同時也針對每人每年國民所得區分不同經濟發展階段的另一分量迴歸，建構一雙向分量迴歸，以綜合考量不同CO2排放程度及不同經濟發展情況下，更準確的捕捉不同經濟發展階段下，CO2的排放量與經濟發展水準的關係。同時在使用長期追蹤資料下，以共同邊界技術比率改善固定效果模型對樣本個別效果與時間效果的解釋能力。 估計結果顯示經濟發展水準較低的國家，每增加1%之每人每年GDP，其承受相對較小的每人每年CO2排放量之增加幅度。其次，隨著經濟發展程度的提昇，每人每年GDP與每人每年CO2排放量關係的曲線漸為平坦，但不論那一階段的經濟發展水準，每人每年GDP與每人每年CO2排放量並不存在倒U字型的關係。此外，在單向分量迴歸與雙向分量迴歸的估計結果，平均而言雙向分量迴歸所估計之係數，較單向分量迴歸來的符合實際情況。

The purpose of this paper is to construct a double quantile regressions model to simultaneously take into account different levels of CO2 emissions and different levels of economic development for each country. One of the quantile regressions accounts for the division of CO2 emissions per capita annually. The other quantile regression justifies the degree of economic development with representation of national income per capita per year(GDP) A set of data with 104 countries in 1990-2005 is used for such purpose. Due to the use of panel data, variables of meta-technical ratio of each country in different years are estimated to reflect the time and country fixed effect to replace the traditional fixed-effect model to have better performance in catching the time-invariant factors. Estimated results show that, countries for all levels of economic developments and for different levels of CO2 the relationships between GDP per capita and CO2 emission per person are positive. That is, for either group of the country there is no inverted U-shaped relationship between GDP per capita and CO2 emission per person. In addition, as with the change of GDP per capita to the change of CO2 emission per person, the resultes estimated from double quantile regression are closed to the data computed from the original data. Furthermore, every 1% increase of GDP for country with low economic development, there is higher percentage increase of CO2 emission. On the contrary, every 1% increase of GDP for country with high economic development, the percentage increase of CO2 is lower. However, countries with different levels of economic development weigh and view differently for every 1% increase of GDP. Since the absolute increase of CO2 emissions is higher for low income country than that for high income country it reinforces the conflict between the development of economy for low income country and the control of CO2 emissions. This will then require much more efforts to release the tension and pressure for corporative elimination of CO2 emissions between high income countries and low income countries.