基于网格化碳足迹的生态可持续性评估：以海南岛为例

Ecological sustainability assessment based on grid carbon footprint: a case study of Hainan Island

关键词:  碳足迹  网格化  生态指数  可持续性  海南岛

Key words:  carbon footprint  gridding  ecological index  sustainability  Hainan Island

摘要:

过度碳排放加剧全球变暖, 对生态环境造成严重影响, 威胁人类社会的可持续发展。因此, 评估区域可持续性至关重要。文章以中国南方热带岛屿海南岛为研究区域, 根据联合国政府间气候变化专门委员会（IPCC）的碳排放指南, 采用一种基于网格尺度和改进的净初级生产力（NPP）过程模拟方法评估区域碳足迹, 并从时空角度分析海南岛2010—2021年的碳足迹, 同时构建碳可持续性指数、土地碳强度、收益碳强度、人均碳排放和碳盈余率这5个生态指标评估区域的可持续性。结果表明: 海南岛碳足迹空间格局呈现沿海高、中部低的环状结构, 2010—2021年海口市平均碳足迹最高(161.93 hm²), 琼中县最低(2.70 hm²), 沿海与中部差距达数十倍。研究期间全省平均碳足迹呈上升趋势, 由2010年的29.08 hm²增至2021年的42.31 hm², 年均增长率约3.47%; 碳盈余率从94.56%持续下降至81.03%, 碳可持续性指数从3.56降至1.97, 土地碳强度从2.25 t/hm²（文章所有数值均以碳为计量基准）增至3.82 t/hm², 人均碳消费从0.88 t/人增至1.29 t/人, 表明生态可持续性呈下降趋势。海口、儋州、东方等沿海城市已出现明显碳赤字, 碳平衡压力持续增大。因此, 迫切需要平衡经济发展与生态保护之间的关系, 研究可为类似区域实现生态文明与可持续发展提供科学参考。

Abstract:

Background, aim, and scope Excessive carbon emissions exacerbate global warming, exert severe impacts on ecological environments, and threaten the sustainable development of human society. Consequently, accurately assessing regional sustainability has become critically important. This study focuses on Hainan Island, a tropical island in southern China, aiming to reveal the spatiotemporal evolution and sustainability characteristics of the regional carbon footprint at a fine scale. Materials and methods Utilizing multi-source datasets, including socioeconomic statistics from the Hainan Statistical Yearbook, NASA MODIS remote sensing products (NDVI and land cover), and meteorological observations (temperature, precipitation, and solar radiation), we evaluated the regional carbon footprint from 2010 to 2021. Following the carbon emission guidelines of the Intergovernmental Panel on Climate Change (IPCC), we adopted a 500 m × 500 m grid-scale method based on an improved Carnegie-Ames-Stanford Approach (CASA) model for net primary productivity (NPP) simulation. Furthermore, five ecological indicators, the carbon sustainability index, land-based carbon intensity, income carbon intensity, per-capita carbon consumption, and carbon surplus ratio, were constructed to comprehensively assess regional ecological sustainability. Results The carbon footprint of Hainan Island exhibited a distinct annular spatial pattern, characterized by high values in coastal areas and low values in the central mountainous region. During 2010—2021, the highest annual average carbon footprint was observed in Haikou City (161.93 hm²), while the lowest was recorded in Qiongzhong County (2.70 hm²), demonstrating a tens-fold disparity between coastal and inland areas. Temporally, the provincial average carbon footprint showed a significant upward trend, increasing from 29.08 hm² in 2010 to 42.31 hm² in 2021, with an average annual growth rate of approximately 3.47%. All five ecological indicators pointed to a deteriorating trend in sustainability capacity over the study period. Specifically, the carbon surplus ratio declined continuously from 94.56% to 81.03%, and the carbon sustainability index dropped from 3.56 to 1.97. Meanwhile, land-based carbon intensity rose from 2.25 t/hm² (all values throughout this paper are reported on a carbon basis) to 3.82 t/hm²; per-capita carbon consumption increased from 0.88 t/cap to 1.29 t/cap; and income carbon intensity decreased from 37.08 g/yuan to 20.33 g/yuan. Discussion Correlation analysis revealed that the carbon footprint was significantly positively correlated with carbon emissions, permanent population, gross domestic product (GDP), and leaf area index (LAI), while showing non-significant correlations with temperature, annual precipitation, and NPP. The pronounced spatial disparity—characterized by high carbon footprint in coastal areas and low values in the central region—is primarily driven by the intense aggregation of human socioeconomic activities. Coastal cities like Haikou and Danzhou experience severe carbon deficits due to dense populations, rapid urbanization, and high-energy-consuming industrial layouts, which generate massive fossil fuel emissions that far exceed the local ecological carrying capacity. In contrast, the central mountainous regions (e.g., Qiongzhong and Wuzhishan) maintain carbon surpluses owing to strict ecological protection policies and high tropical rainforest coverage. Furthermore, the temporal upward trend aligns with the macro-economic expansion of the region, indicating a fundamental spatial mismatch between massive anthropogenic carbon sources and limited natural carbon sinks. Ultimately, the proposed grid-scale method demonstrated strong operability and reliable simulation outcomes, effectively identifying these spatial hotspots heavily impacted by human activities. Conclusions Carbon deficits are highly concentrated in economically developed coastal cities such as Haikou, Danzhou, and Dongfang, whereas the central counties and cities have long sustained a carbon surplus pattern. Most coastal regions exhibit substantial interannual variability in their carbon footprint, while changes in some central areas remain relatively marginal. Across Hainan Island, overall ecological pressure continues to intensify; carbon deficits in Haikou, Danzhou and Dongfang are particularly pronounced, thereby imposing marked pressure on the regional carbon balance. Recommendations and perspectives There is an urgent need to balance the relationship between economic development and ecological protection. Policymakers should accelerate the green transformation of the industrial structure and steadily promote the construction of the National Ecological Civilization Pilot Zone. This study provides a robust methodological framework and scientific reference for realizing sustainable human-land relationships in similar regions worldwide.