Large-scale expansion of agriculture in Amazonia may be a no-win scenario
Large-scale expansion of agriculture in Amazonia may be a no-win scenario
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DOI：
10.1088/1748-9326/8/2/024021
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发表时间：
2013-05
影响因子：
6.7
通讯作者：
L. J. Oliveira;M. H. Costa;B. Soares-Filho;M. Coe
中科院分区：
文献类型：
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作者：
L. J. Oliveira;M. H. Costa;B. Soares-Filho;M. Coe
使用简化的气候和土地利用模型，我们评估了在森林砍伐和二氧化碳增加的几种情景下巴西合法亚马逊地区原始森林的碳储存以及大豆和牧场的生产力。我们分析的 2050 年四种情景考虑了 (1) 二氧化碳增加的辐射效应，(2) 二氧化碳增加的辐射和生理效应，(3) 土地利用变化对区域气候的影响，以及 (4) 二氧化碳增加加上土地利用气候反馈的辐射和生理效应。在当前条件下，地上森林生物量（AGB）、大豆产量和牧草产量的平均值分别为 179 Mg-C ha−1、2.7 Mg-grains ha−1 和 16.2 Mg-drymass ha−1 yr−1。我们的研究结果表明，亚马逊流域农业的扩张可能是双赢的局面：除了因森林砍伐而减少碳储存外，由于土地利用变化带来的气候反馈，农业总产值的增长可能远低于农业面积潜在扩张的比例，甚至可能下降。这些气候反馈在以前的研究中通常被忽视，它们会导致降水减少，从而导致亚马逊流域的农业扩张弄巧成拙：农业扩张越多，生产力就越低。
Using simplified climate and land-use models, we evaluated primary forests’ carbon storage and soybean and pasture productivity in the Brazilian Legal Amazon under several scenarios of deforestation and increased CO2. The four scenarios for the year 2050 that we analyzed consider (1) radiative effects of increased CO2, (2) radiative and physiological effects of increased CO2, (3) effects of land-use changes on the regional climate and (4) radiative and physiological effects of increased CO2 plus land-use climate feedbacks. Under current conditions, means for aboveground forest live biomass (AGB), soybean yield and pasture yield are 179 Mg-C ha−1, 2.7 Mg-grains ha−1 and 16.2 Mg-dry mass ha−1 yr−1, respectively. Our results indicate that expansion of agriculture in Amazonia may be a no-win scenario: in addition to reductions in carbon storage due to deforestation, total agriculture output may either increase much less than proportionally to the potential expansion in agricultural area, or even decrease, as a consequence of climate feedbacks from changes in land use. These climate feedbacks, usually ignored in previous studies, impose a reduction in precipitation that would lead agriculture expansion in Amazonia to become self-defeating: the more agriculture expands, the less productive it becomes.