资源环境承载力弹性区间测度与未来情景分析——以兰西城市群为例

Elastic range measurement of resource and environmental carrying capacity and future scenario analysis:A case study of the Lanzhou-Xining urban agglomeration

【目的】构建与资源环境承载力相适应的城镇规模体系,是实现城市群可持续发展的重要基础。但以单一绝对值为静态刚性约束的资源环境承载力测度方法,不符合资源环境综合承载力本身的动态性和不确定性特点。为此,本文旨在对资源环境承载力进行弹性区间测度和未来情景预测。【方法】本文提出了资源环境承载力弹性区间与状态类型的测定方法,构建了一套基于系统动力学和元胞自动机-马尔科夫模型的资源环境承载力量化分析框架,基于共享社会经济路径提供了资源环境承载力未来多情景分析方案,并以兰西城市群为案例进行了实证研究。【结果】(1)2000—2020年,兰西城市群资源环境承载力弹性区间由2000年的[1167,1367]变化至2020年的[2049,2069](单位:万人),承载状态由临界超载优化为不超载。(2)资源环境承载力弹性区间和各项单要素承载力在各地级行政单元基本均呈上升态势,并呈现出明显的空间分异。(3)2021—2035年,SSP1情景中的多数单要素承载力高于其他情景,同时人口增长率最低;SSP2作为基准情景,资源环境综合承载力的弹性区间、各项单要素承载力和常住人口均处于中间水平;SSP3是资源环境综合承载力的弹性区间最低且常住人口最多的情景;SSP5情景下,能源承载力最低,环境承载力居首。(4)SSP1情景下兰西城市群将呈现全域可承载的均衡格局,其余情景下则呈现“中间差外围优”的核心-边缘式空间分布格局。【结论】未来应当基于SSP1发展路径,从城镇发展格局适应性构建和承载潜力动态性提升两方面合力应对资源环境承载风险,促进人地关系协调发展。

[Objective]Developing an urban system scale that adapts to the resources and environmental carrying capacity(RECC)is an important foundation for achieving sustainable development of urban agglomerations.Previous studies often employed static and rigid constraints to represent RECC,which were characterized by single absolute values.Such approach does not align with the dynamic and uncertain nature of RECC.To address this issue,the purpose of this study was to measure the elastic ranges and project future scenarios of resources and environmental carrying capacity.[Methods]This study proposed a method for determining the elastic range and status of RECC.A quantitative analytical framework for RECC was constructed by integrating the system dynamic and CA-Markov models.Additionally,the shared socioeconomic pathways(SSPs)provide a series of future scenarios for analyzing RECC.The proposed framework was applied to an empirical study of the Lanzhou-Xining urban agglomeration(LXUA).[Results](1)From 2000 to 2020,the elastic range of the RECC in the LXUA changed from[11.67,13.67]million to[20.49,20.69]million people,and the carrying capacity status type transitioned from critical overload to non-overload.(2)The elastic range of the RECC and the single-factor carrying capacity were basically on the rise in each prefecture-level administrative unit,and presented obvious spatial divergence.(3)From 2021 to 2035,under the SSP1 scenario most of the single-factor carrying capacities will be higher than under the other scenarios,while the population growth rate will be the lowest;As the baseline scenario of SSP2,the elastic range of comprehensive resources and environmental carrying capacity,each single-factor carrying capacity and the permanent population will be all at the middle level.SSP3 will be the scenario with the lowest elastic range of comprehensive resources and environmental carrying capacity and the largest permanent population;SSP5 will have the lowest energy carrying capacity and the highest environmental carrying capacity.(4)Under the SSP1 scenario,the LXUA will exhibit a balanced pattern of nonoverload across the whole region.By contrast,the other scenarios will demonstrate a coreperiphery spatial distribution pattern of“poor in the middle and excellent at the periphery”.[Conclusion]In the future,based on the SSP1 development path,resources and environmental carrying risks should be addressed from the two aspects of adaptive construction of urban development pattern and dynamic improvement of carrying potential,so as to promote the coordinated development of human-nature relationship.