Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools
Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools
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DOI：
10.1073/pnas.1211658109
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发表时间：
2012-10-02
影响因子：
11.1
通讯作者：
Hutyra, Lucy R.
中科院分区：
文献类型：
--
作者：
Seto, Karen C.;Gueneralp, Burak;Hutyra, Lucy R.
城市土地覆盖变化威胁生物多样性，并通过生境、生物量和碳储存的丧失影响生态系统生产力。然而，尽管预测到2030年世界城市人口将增加到近50亿，但人们对未来城市扩张的地点、规模和速度知之甚少。在这里，我们开发了全球城市土地覆盖变化的空间显式概率预测，并探讨对生物多样性热点和热带碳生物量的直接影响。如果目前的人口密度趋势继续下去，所有城市扩张可能性高的地区都发生变化，那么到2030年，城市土地覆盖将增加120万平方公里，几乎是2000年全球城市土地面积的三倍。这一增长将导致主要生物多样性热点地区的生境大量丧失，预计2000年城市增长率最高的地区将是相对未受城市发展影响的地区：东非山区、西非几内亚森林、西高止山脉和斯里兰卡热点地区。在泛热带地区，城市扩张可能性高的地区的植被生物量损失估计为1.38 PgC（0.05 PgC yr（-1）），相当于热带森林砍伐和土地利用变化排放量的5%。尽管城市化通常被认为是一个局部问题，但预计的城市扩张对全球的总体影响将需要重大的政策变化来影响未来的增长轨迹，以最大限度地减少全球生物多样性和植被碳损失。
Urban land-cover change threatens biodiversity and affects ecosystem productivity through loss of habitat, biomass, and carbon storage. However, despite projections that world urban populations will increase to nearly 5 billion by 2030, little is known about future locations, magnitudes, and rates of urban expansion. Here we develop spatially explicit probabilistic forecasts of global urban land-cover change and explore the direct impacts on biodiversity hotspots and tropical carbon biomass. If current trends in population density continue and all areas with high probabilities of urban expansion undergo change, then by 2030, urban land cover will increase by 1.2 million km(2), nearly tripling the global urban land area circa 2000. This increase would result in considerable loss of habitats in key biodiversity hotspots, with the highest rates of forecasted urban growth to take place in regions that were relatively undisturbed by urban development in 2000: the Eastern Afromontane, the Guinean Forests of West Africa, and the Western Ghats and Sri Lanka hotspots. Within the pan-tropics, loss in vegetation biomass from areas with high probability of urban expansion is estimated to be 1.38 PgC (0.05 PgC yr(-1)), equal to similar to 5% of emissions from tropical deforestation and land-use change. Although urbanization is often considered a local issue, the aggregate global impacts of projected urban expansion will require significant policy changes to affect future growth trajectories to minimize global biodiversity and vegetation carbon losses.