College of Life and Environmental Sciences, Geography University of Exeter, Exeter, EX4 4RJ, U.K.; Remote Sensing Division, National Institute for Space Research, Av. dos Astronautas, 1758, São José dos Campos, Sao Paulo, 12227-010, Brazil.
Biol Rev Camb Philos Soc. 2014 Nov;89(4):913-31. doi: 10.1111/brv.12088. Epub 2014 Feb 20.
Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency.
极端气候事件和土地利用变化已知会强烈影响亚马逊地区当前的碳循环，并有可能对全球气候产生重大影响。本综述旨在评估气候和人为干扰对巴西亚马逊地区碳平衡的影响，并了解它们之间的相互作用。通过分析政府间气候变化专门委员会（IPCC）第四次评估报告（AR4）模型集合的输出，我们表明，亚马逊地区的温度和水分胁迫都有可能在 21 世纪增加。与 1990 年代相比，2010 年将巴西亚马逊地区的森林砍伐减少 62%，使巴西亚马逊地区的森林砍伐对全球土地利用碳排放的贡献从 1990 年代和 21 世纪初的 17%下降到 2010 年的 9%。亚马逊地区的碳源可能主要由与森林火灾相关的气候影响主导（极端干旱期间相对贡献为 48.3%）。目前，巴西亚马逊地区的净碳汇（净生物群区生产力，NBP）为+0.16（范围为+0.11 至+0.21）Pg C year(-1)，相当于 2008 年土地利用变化导致的全球碳排放的 13.3%，在干旱年份可能会被抵消或逆转[NBP =-0.06（-0.31 至+0.01）Pg C year(-1)]。因此，除了减少森林砍伐外，减少森林火灾将是减少未来排放的重要措施。相反，将目前的次生林面积增加一倍，并避免进一步清除原生林，将有助于亚马逊地区的总森林汇抵消约 42%的全球土地利用变化排放。我们的结论是，一些战略性的环境政策措施可能会增强亚马逊地区的净碳汇，并产生全球影响。此外，这些行动可以提高净碳汇对未来干旱频率增加的抵御能力。
