建设用地扩张与碳排放效应的库兹涅茨曲线假说及验证

论文基于无锡市1996—2008年的土地利用和能源消耗数据,分析了无锡市13 a间建设用地扩张及碳排放特征,并构建了建设用地比例与碳排放强度之间的库兹涅茨曲线模型,对无锡市建设用地扩张与碳排放效应之间的相关关系进行了实证研究,尝试验证库兹涅茨曲线在建设用地扩张与碳排放强度之间的存在性。结果表明:①建设用地总量在1996—2008年间迅速增长,绝对增长量44 032.97 hm²,且除了农村居民点逐渐下降以外,其余地类均呈逐年增长态势,无锡市1996—2008年间的碳排放基本上也呈现逐年增长趋势,绝对增长量1 936.38×10⁴ t;②建设用地总量与碳排放强度之间呈倒U型曲线关系,即随着建设用地扩张至拐点后,碳排放强度则逐渐下降,且拐点位于建设用地比例1.91%附近,但是目前仅仅刚开始出现拐点的迹象,表明目前无锡市建设用地扩张还未完全达到集约及精明增长的标准,建设用地扩张对碳排放而言仍然具有较强的推动作用,但是可以预见,随着产业结构调整和能源技术的提高,碳排放强度会逐渐进入下降的阶段;③城市用地与碳排放强度之间为三次曲线关系,建制镇用地、农村居民点用地与碳排放强度之间分别为正相关和负相关线性关系,其他建设用地与碳排放强度之间则存在一种不明显的库兹涅茨曲线关系。建设用地地类组成的不同会导致不同形态的库兹涅茨曲线,由于城市用地和建制镇用地对碳排放具有明显的驱动作用,其比例的提高亦会促使库兹涅茨曲线更加陡峭,并延缓库兹涅茨曲线拐点的到来。

Hypothesis and Validation on the Kuznets Curve of Construction Land Expansion and Carbon Emission Effect

On the basis of the data on land use and energy consumption in Wuxi City during the course of 13 years from 1996 to 2008,this paper carries out an empirical research into the relationship between construction land expansion and carbon emission effect in Wuxi City by means of not only pointing up the characteristics of construction land expansion and carbon emission but also setting up Kuznets curve model of construction land rate as well as carbon emission intensity to try to verify the beingness of Kuznets curve between construction land expansion and carbon emission intensity.As shown in the result:1) Construction land increased sharply by 44032.97 hm2 from 1996 to 2008,and all of the land use types presented a year-by-year increasing tendency except rural settlements decreased year by year.Generally speaking,carbon emission in Wuxi City from 1996 to 2008 also presented a year-by-year increasing tendency,with an increment of 1936.38×104 t.2) The relationship between gross construction land and carbon emission intensity presents an inverted "U-shaped" curve,that is to say,when construction land expands to the inflexion point which turns up around at construction land rate 1.91%,carbon emission intensity will decrease gradually.The inflexion point just emerges for the moment which shows that construction land expansion in Wuxi City has not reached the standard of intensive and smart growth and it still drives carbon emission to increase.However,it is foreseeable that carbon emission intensity will decrease gradually with industrial restructuring and energy technological advancement.3) The relationship between carbon emission intensity and urban land shows cubic curve;the relationships between carbon emission intensity and town land as well as rural settlements respectively form positive and negative linear ones.An unobvious Kuznets curve exists between other construction land and carbon emission intensity.Different compositions of construction land types cause different shapes of Kuznets curve.Because urban land and town land have an obvious driving force on carbon emission,the increase of rate will cause the Kuznets curve more steeply,and delay the arrival of inflexion point of Kuznets curve.