The dimensions of global urban expansion: Estimates and projections for all countries, 2000-2050
The dimensions of global urban expansion: Estimates and projections for all countries, 2000-2050
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DOI：
10.1016/j.progress.2011.04.001
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发表时间：
2011-02-01
影响因子：
6.4
通讯作者：
Potere, David
中科院分区：
文献类型：
--
作者：
Angel, Shlomo;Parent, Jason;Potere, David
我们对具有代表性的30个城市的扩张进行了研究，结果显示，其中28个城市在世纪扩张了16倍以上。更普遍的是，城市现在正以平均两倍于人口增长率的速度扩张，现在几乎覆盖了地球陆地面积的0.5%。我们创建了一个新的数据集，其中包括2000年人口超过10万的所有3646个命名的大都市群和城市，当年的人口，以及Mod 500地图中确定的建成区，Mod 500地图是目前八个基于卫星的全球城市土地覆盖地图中最好的。使用该数据集，我们估计了所有国家小城市和城镇的城市土地覆盖，并计算了2000年每个国家的城市土地覆盖总量。然后，我们采用了多元回归模型，可以解释超过90%的变化，我们的城市土地覆盖估计国家之间。然后，使用联合国城市人口预测，结合基于我们以前的全球和历史密度研究的三种现实密度变化情景，我们预测了2000年至2050年每个国家和世界地区的城市土地覆盖。根据我们的中期预测，发展中国家的城市土地覆盖面积将从2000年的300 000平方公里增加到2030年的770 000平方公里和2050年的1 200 000平方公里。遏制这种扩张很可能会失败。为适应这一点，最低限度的准备工作--现实地预测城市土地需求，扩展大都市边界，获得能够承载基础设施和公共交通的干线公路网的通行权，以及有选择地保护开放空间不受正式和非正式土地开发的侵犯--现在都已就绪。(C)2011爱思唯尔有限公司保留所有权利。
Our study of the expansion of a representative sample of 30 cities showed that 28 of them expanded more than 16-fold during the twentieth century. More generally, cities are now expanding at twice their population growth rates, on average, and now cover almost 0.5% of the planet's land area. We created a new dataset comprising the universe of all 3646 named metropolitan agglomerations and cities that had populations in excess of 100,000 in the year 2000, their populations in that year, and their built-up area identified in the Mod500 map, currently the best of eight satellite-based global maps of urban land cover. Using this dataset, we estimated urban land cover in smaller cities and towns in all countries and calculated total urban land cover in every country in the year 2000. We then employed multiple regression models that could explain more than 90% of the variations in our urban land cover estimates amongst countries. Then, using U.N. urban population projections in combination with three realistic density change scenarios based on our previous global and historical study of densities, we projected urban land cover in every country and world region from 2000 to 2050. According to our medium projection, urban land cover in developing countries will increase from 300,000 km(2) in 2000 to 770,000 km(2) in 2030 and to 1,200,000 km(2) in 2050. Containing this expansion is likely to fail. Minimal preparations for accommodating it-realistic projection of urban land needs, the extension of metropolitan boundaries, acquiring the rights-of-way for an arterial road grid that can carry infrastructure and public transport, and the selective protection of open space from incursion by formal and informal land development - are now in order. (C) 2011 Elsevier Ltd. All rights reserved.