| 亞馬孫大火或將加劇安第斯山脈冰川融化 |《科學報告》 |
論文標題：Amazonian Biomass Burning Enhances Tropical Andean Glaciers Melting
期刊：Scientific Reports
作者：Newton de Magalhães Neto, Heitor Evangelista et.al
發表時間：2019/11/28
數字識別碼：10.1038/s41598-019-53284-1
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根據《科學報告》發表的一項研究Amazonian Biomass Burning Enhances Tropical Andean Glaciers Melting，亞馬孫流域西南部（巴西、秘魯和玻利維亞）的雨林火災可能會加劇安第斯山脈的熱帶冰川融化。
煙羽從亞馬孫流域擴散到安第斯山脈中部
圖片來源：Neto等
巴西裡約熱內盧州立大學的Newton de Magalhães Neto及同事利用2000年至2016年間收集的火災事件、煙羽流動、降水和冰川融化數據建模，評估亞馬孫流域的生物體燃燒對玻利維亞Zongo冰川可能造成的影響。他們發現生物體燃燒產生的氣溶膠（比如炭黑）可以隨風擴散到安第斯山脈熱帶冰川，沉降在雪中；由於被炭黑或粉塵覆蓋的積雪反射的光減少（返照率下降），冰川融化可能因此加劇。
作者重點分析了2007年至2010年的情況，當時亞馬孫流域的火災季最為嚴峻。他們調查了炭黑單獨作用下和炭黑與先前報導的粉塵綜合作用下的積雪返照率，模型顯示單獨的炭黑或粉塵可能使年冰川融化率增加3-4%；二者共同作用則可能使之增加6%。如果粉塵濃度夠高，粉塵單獨可能使年冰川融化率增加11-13%，而在存在炭黑的情況下則可達到12-14%。這項發現表明亞馬孫流域生物體燃燒的影響取決於積雪中的粉塵濃度。
國際糧食需求相關壓力可能導致亞馬孫流域的農耕和森林砍伐進一步擴張，由此增加的炭黑和二氧化碳排放可能影響到安第斯山脈冰川。
摘要：The melting of tropical glaciers provides water resources to millions of people, involving social, ecological and economic demands. At present, these water reservoirs are threatened by the accelerating rates of mass loss associated with modern climate changes related to greenhouse gas emissions and ultimately land use/cover change. Until now, the effects of land use/cover change on the tropical Andean glaciers of South America through biomass burning activities have not been investigated. In this study, we quantitatively examine the hypothesis that regional land use/cover change is a contributor to the observed glacier mass loss, taking into account the role of Amazonian biomass burning. We demonstrated here, for the first time, that for tropical Andean glaciers, a massive contribution of black carbon emitted from biomass burning in the Amazon Basin does exist. This is favorable due to its positioning with respect to Amazon Basin fire hot spots and the predominant wind direction during the transition from the dry to wet seasons (Aug-Sep-Oct), when most fire events occur. We investigated changes in Bolivian Zongo Glacier albedo due to impurities on snow, including black carbon surface deposition and its potential for increasing annual glacier melting. We showed that the magnitude of the impact of Amazonian biomass burning depends on the dust content in snow. When high concentration of dust is present (e.g. 100 ppm of dust), the dust absorbs most of the radiation that otherwise would be absorbed by the BC. Our estimations point to a melting factor of 3.3 ± 0.8% for black carbon, and 5.0 ± 1.0% for black carbon in the presence of low dust content (e.g. 10 ppm of dust). For the 2010 hydrological year, we reported an increase in runoff corresponding to 4.5% of the annual discharge during the seasonal peak fire season, which is consistent with our predictions.
（來源：科學網）
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