Combined climate and carbon-cycle effects of large-scale deforestation
Combined climate and carbon-cycle effects of large-scale deforestation
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DOI：
10.1073/pnas.0608998104
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发表时间：
2007-04-17
影响因子：
11.1
通讯作者：
Mirin, A.
中科院分区：
文献类型：
--
作者：
Bala, G.;Caldeira, K.;Mirin, A.
防止砍伐森林和促进植树造林经常被认为是减缓全球变暖的战略。砍伐森林向大气中释放二氧化碳，对地球气候产生变暖影响。然而，森林砍伐的生物物理效应，包括地表水分、蒸散和云量的变化，也影响气候。在这里，我们提出的结果，从几个大规模的森林砍伐实验进行了三维耦合全球碳循环和气候模式。这些模拟是通过使用一个全三维模型，代表陆地，大气和海洋之间的物理和地球化学相互作用。我们发现，全球规模的森林砍伐对地球气候有净冷却影响，因为森林砍伐的变暖碳循环效应被与蒸发和蒸散量变化相关的净冷却所淹没。针对热带地区的森林砍伐实验表明，热带地区的造林项目显然有利于减缓全球变暖，但如果在高纬度地区实施，则会适得其反，在温带地区只能带来微不足道的好处。虽然这些结果对中高纬度地区造林项目减缓气候变化的效力提出了质疑，但由于许多与气候无关的原因，森林仍然是环境上宝贵的资源。
The prevention of deforestation and promotion of afforestation have often been cited as strategies to slow global warming. Deforestation releases CO2 to the atmosphere, which exerts a warming influence on Earth's climate. However, biophysical effects of deforestation, which include changes in land surface albedo, evapotranspiration, and cloud cover also affect climate. Here we present results from several large-scale deforestation experiments performed with a three-dimensional coupled global carbon-cycle and climate model. These simulations were performed by using a fully three-dimensional model representing physical and biogeochemical interactions among land, atmosphere, and ocean. We find that global-scale deforestation has a net cooling influence on Earth's climate, because the warming carbon-cycle effects of deforestation are overwhelmed by the net cooling associated with changes in albedo and evapotranspiration. Latitude-specific deforestation experiments indicate that afforestation projects in the tropics would be clearly beneficial in mitigating global-scale warming, but would be counterproductive if implemented at high latitudes and would offer only marginal benefits in temperate regions. Although these results question the efficacy of mid- and high-latitude afforestation projects for climate mitigation, forests remain environmentally valuable resources for many reasons unrelated to climate.