CN 11-5366/S     ISSN 1673-1530
“风景园林,不只是一本期刊。”

气候韧性视角下基于NSGA-Ⅲ的国土空间优化方法

Territorial Spatial Optimization Method Based on NSGA-III from the Perspective of Climate Resilience

  • 摘要:
    目的 以增汇减排为核心的自然气候解决方案(natural climate solutions, NCS)是应对气候变化问题的有效方法之一,而城市经济社会快速发展使NCS落实的载体——林草地等生态用地面临着随时被侵占的困境。通过构建多目标优化模型完成国土空间优化,可协调多方发展需求并实现气候韧性。
    方法 以四川天府新区眉山片区为例,以2030年为期设定强气候韧性、均衡发展两种情景,构建基于“双评价”约束的第三代非支配排序遗传算法(NSGA-Ⅲ)的国土空间优化模型。
    结果 强气候韧性、均衡发展情景中分别有10.92%和13.21%的土地发生变化,推动气候调节效益分别增长23.12%、9.88%,前者情景中首要贡献者是林地,后者为草地;人口容量分别增长64.94%、69.15%,强气候韧性情景在实现气候韧性的同时兼顾了城市发展。两种情景结果都显示,研究区下辖的5个街道/镇中,生态用地较少的青龙街道内林地面积增长率超100%,城镇开发强度较小的高家镇、贵平镇内建设用地面积增长率超600%,锦江镇、视高街道内各类型土地变化相对平稳;与2020年相比,优化后的各类型土地斑块形状趋于复杂,国土空间呈现更加破碎的布局模式,尤以均衡发展情景为甚。
    结论 多目标国土空间优化模型以气候韧性为主导,兼顾社会发展需求,减轻了生态用地易被侵占的风险,为研究区推进零碳排放试点工程和落实气候韧性发展实践提供可借鉴的技术路径。

     

    Abstract:
    Objective Natural climate solutions (NCS) centered on carbon sequestration and emission reduction can effectively respond to climate change. However, the rapid socio-economic development has presented significant challenges to NCS implementation by constantly threatening ecological lands. This research proposes to optimize territorial space to coordinate diverse development and bolster climate resilience through developing a multi-objective optimization model.
    Methods Taking the Meishan area of Sichuan Tianfu New Area as an example, this research sets up two scenarios for the period up to 2030: Climate-resilient development and balanced development. The climate-resilient development scenario prioritizes the development goal of mitigating and adapting to climate change, and actively explores how to maximize the climate regulation benefits of ecosystem. The balanced development scenario aims to actively address the adverse impacts of climate change while promoting urban development and construction. Based on development requirements, both scenarios incorporate six optimization objectives: Climate regulation benefits, carbon emissions, population capacity, and so on. With the evaluation results of resource and environment carrying capacity and territorial spatial development suitability of the research area as guiding constraints, an optimization model based on the principles of the third-generation non-dominated sorting genetic algorithm (NSGA-III) is constructed. This model can help accomplish the optimization of territorial space and analyze the performance and optimization results of the multi-objective optimization model.
    Results The evaluation results of resource and environment carrying capacity and territorial spatial development suitability of the research area indicate that ecologically crucial areas and ecologically important areas are primarily distributed in the Pengzu Mountain and Longquan Mountain ecological belts accounting for 3.32% of the total area of the research area. The water area is mainly composed of the Min River and the Fu River, accounting for 0.93% of the total area. The research area lacks carbon sink resources, which is unfavorable for climate-resilient development. The areas suitable for agricultural production and urban construction completely overlap, accounting for over 95% of the total area of the research area, and can be utilized for either food production or urban development. According to the evaluation results of the resource and environment carrying capacity and territorial spatial development suitability of the research area, the land use change proportion is 10.92% in the climate-resilient development scenario and 13.21% in the balanced development scenario. Among the five subdistricts/towns within the research area’s jurisdiction, the forestland area in Qinglong Subdistrict, characterized by limited ecological lands, has expanded by over 100%, while the built-up area in Gaojia Town and Guiping Town with relatively low urban development intensity, has surged by over 600%. Land use changes in Jinjiang Town and Shigao Subdistrict have remained comparatively stable. Upon optimization, the shapes of various land patches have become more intricate compared to 2020, resulting in a more fragmented land layout, particularly evident in the balanced development scenario. The shifts in land use utilization have increased the climate regulation benefits by 23.12% and 9.88% respectively in the climate-resilient development scenario and the balanced development scenario, with forestlands primarily contributing to the former while grasslands to the latter, and both the forestlands and grasslands predominantly converted from arable lands. Population capacity has risen by 64.94% and 69.15% respectively in the two scenarios. Carbon emissions have surged by 27.79% and 34.50%, predominantly driven by construction lands, while emissions from forestlands, grasslands, and water bodies have decreased by 10.64% and 8.63% respectively in the two scenarios. The performance of the three development objectives in terms of spatial layout optimization is relatively favorable. In summary, the climate-resilient development scenario successfully meets climate resilience targets while achieving social development objectives. In this scenario, existing forestlands are effectively preserved, and new ones are significantly generated. Similarly, in the balanced development scenario, there is a notable increase in forestland area, albeit with some degradation of existing forestlands, requiring the conversion of additional arable lands to offset these losses. Moreover, grasslands emerge around and within built-up areas in both scenarios, further augmenting the climate regulation benefits within the research area. Nonetheless, in both scenarios, the interconnection of newly formed small forestland and grassland patches with newly developed construction land patches compromises the integrity of arable land patches in the spatial layout.
    Conclusion The multi-objective territorial spatial optimization model, guided by climate resilience while considering social development needs, can effectively address the risk of encroachment on ecological lands such as forestlands and grasslands. It provides a viable technical pathway for the research area to advance the pilot zero-carbon emission program and implement climate-resilient development practices. In the future, through targeted on-site monitoring of land use changes and climate change responses in the research area at small scales, we can systematically improve the model’s performance to facilitate the implementation of territorial spatial planning with a focus on climate resilience.

     

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