科学家称烟尘导致19世纪60年代阿尔卑斯山冰川消退
2013-09-10 13:05阅读：
2013.09.06
这张拍摄于2012年夏季、南眺伯尔尼阿尔卑斯山的照片显示出阿尔卑斯山的空气污染物易于在较低海拔积聚，使烟尘和粉尘沉积在较低的山坡上。
华盛顿——一个由美国航空航天局（NASA）领导的科学家团队发现了欧洲迅速工业化产生的烟尘导致欧洲阿尔卑斯山（European
Alps）的冰川从19世纪60年代开始突然消退的有力证据，那段时期通常被认为是小冰川期（Little Ice
Age）的结束。
这篇于9月3日发表在《国家科学院院刊》（Proceedings of the National Academy of
Sciences）上的研究报告，可能有助于解决一个长期存在的科学争论。
在19世纪50年代后的几十年里，欧洲经历了由工业化带动的经济和气候转型。美国航空航天局在其网站上介绍这篇研究报告时说，西欧开始真正使用煤炭来给家庭供暖并为交通及工业供电，将大量的黑碳（Black
Carbon）和其他黑色颗粒排放到大气层中。
黑碳是吸收太阳光能力最强的大气颗粒。当这些颗粒沉降到覆盖冰川的积雪上后，会使积雪表面变暗，加速积雪融化并将底层的冰川提早暴露于阳光和暖春及夏日的空气中。每年提前发生的积雪消融使冰川融化更快并出现消退。
小冰川期的宽泛定义是指14世纪到19世纪之间较为寒冷的时期，这个时期的特点是雪山冰川扩张，以及欧洲气温下降将近1.8华氏度（1摄氏度）。美国航空航天局表示，冰川记录显示，在1860年至1930年间，虽然气温继续下降，但阿尔卑斯山的大型山谷冰川突然以大约0.6英里（1公里）的平均长度消退，这是在过去几百年里从未有过的情况。冰川学家和气候学家对气候记录和冰川记录存在的明显矛盾感到困惑不已。
美国航空航天局加利福尼亚州帕萨迪纳（Pasadena）市喷气推进实验室（
Jet Propulsion Laboratory）领导这项研究的积雪和冰川科学家托马斯∙佩因特（Thomas
Painter）说：“等式中缺少了什么。”他说：“在此之前，大多数冰川学家认为，小冰川期的结束发生在19世纪中叶这些冰川消退之时，而冰川消退是因为自然气候的变化，与20世纪末因二氧化碳引起的气候变暖不同。研究结果表明，人类对冰川的影响可追溯到工业化造成气温升高之前很久的时期。
为了帮助科学家理解导致冰川消退的原因，佩因特和他的同事们转向历史研究。研究人员研究了从多处欧洲雪山冰川中钻取的冰芯的数据，来确定阿尔卑斯山冰川开始消退时大气和积雪中黑碳的含量。通过分析冰芯层中的碳颗粒水平，并考虑有关污染物在阿尔卑斯山如何分布的现代观测，研究人员能够估计有多少黑碳沉积在较低海拔的冰川表面，低海拔的冰川上黑碳沉积量往往最高。
研究团队随后对冰川变化进行计算机模拟分析，从记录在案的气候条件入手，然后加入较低海拔污染物的影响。美国航空航天局说，当把这种影响考虑在内后，尽管当时的气温一直在下降，模拟的大块冰川消融及其时间终于与冰川消退的历史记录吻合。
这项研究的合著者以及联合国政府间气候变化委员会（Intergovernmental Panel on Climate
Change）即将发布的第5次评估报告（Fifth Assessment Report）冰冻圈工作组I（Working Group I
Cryosphere）一章的主要作者澳大利亚因斯布鲁克大学（University of
Innsbruck）的格奥尔格·卡泽尔（Georg
Kaser）说：“我们现在必须更仔细地研究地球其他地区，例如喜马拉雅山（Himalaya），分析黑碳当今在这些地区对冰川的影响。”
科罗拉多大学博尔德分校（University of Colorado Boulder）环境科学合作研究所（Cooperative
Institute for Research and Environmental
Sciences）主任及研究报告合著者瓦利德•阿卜杜拉蒂（Waleed
Abdalati）说：“这项研究揭示了人类可能对我们不断变化的环境产生的影响。”他说：“这提醒我们，我们的行为对我们生存的环境具有深远的影响。”
美国航空航天局卫星图像和其他项目捕获气候变化对地球的影响，并为世界各地的科学家提供数据。美国航空航天局和其他联邦机构对气候变化的研究是美国理解及减轻气候变化效应的宏大战略的一部分。
美国航空航天局气候项目的详情请见航空航天局网站（
http://climate.nasa.gov/）。
Read more:
http://iipdigital.usembassy.gov/st/chinese/article/2013/09/20130906282342.html#ixzz2eSmymc3v
Scientists Say Soot Caused Alps Glacier Retreat in 1860s
05 September 2013
This photo from summer 2012, looking south into the Bernese Alps,
shows how air pollution in the Alps tends to be confined to lower
altitudes, concentrating the deposition of soot and dust on the
lower slopes.
Washington — A NASA-led team of scientists has uncovered strong
evidence that soot from a rapidly industrializing Europe caused the
abrupt retreat of mountain glaciers in the European Alps that began
in the 1860s, a period often thought of as the end of the Little
Ice Age.
The research, published September 3 in the
Proceedings of the
National Academy of Sciences, may help resolve a long-standing
scientific debate.
In the decades following the 1850s, Europe underwent an economic
and atmospheric transformation spurred by industrialization. The
use of coal to heat homes and power transportation and industry in
Western Europe began in earnest, spewing huge quantities of black
carbon and other dark particles into the atmosphere, NASA said in
announcing the study on its website.
Black carbon is the strongest sunlight-absorbing atmospheric
particle. When these particles settle on the snow blanketing
glaciers, they darken the snow surface, speeding its melting and
exposing the underlying glacier ice to sunlight and warmer spring
and summer air earlier in the year. This diminishing of the snow
cover earlier in each year causes the glacier ice to melt faster
and retreat.
The Little Ice Age, loosely defined as a cooler period between the
14th and 19th centuries, was marked by an expansion of mountain
glaciers and a drop in temperatures in Europe of nearly 1.8 degrees
Fahrenheit (1 degree Celsius). But glacier records show that
between 1860 and 1930, while temperatures continued to drop, large
valley glaciers in the Alps abruptly retreated by an average of
nearly 0.6 mile (1 kilometer) to lengths not seen in the previous
few hundred years, NASA said. Glaciologists and climatologists have
struggled to reconcile this apparent conflict between climate and
glacier records.
“Something was missing from the equation,” said Thomas Painter, a
snow and ice scientist at NASA's Jet Propulsion Laboratory in
Pasadena, California, who led the study. “Before now, most
glaciologists believed the end of the Little Ice Age came in the
mid-1800s when these glaciers retreated, and that the retreat was
due to a natural climatic shift, distinct from the carbon
dioxide–induced warming that came later in the 20th century. This
result suggests that human influence on glaciers extends back to
well before the industrial temperature increases.”
To help the scientists understand what was driving the glacier
retreat, Painter and his colleagues turned to history. The
researchers studied data from ice cores drilled from high up on
several European mountain glaciers to determine how much black
carbon was in the atmosphere and snow when the Alps glaciers began
to retreat. Using the levels of carbon particles trapped in the ice
core layers, and taking into consideration modern observations of
how pollutants are distributed in the Alps, they were able to
estimate how much black carbon was deposited on glacial surfaces at
lower elevations, where levels of black carbon tend to be
highest.
The team then ran computer models of glacier behavior, starting
with recorded weather conditions and adding the impact of the
lower-elevation pollution. When this impact was included, NASA
said, the simulated glacier mass loss and timing finally were
consistent with the historic record of glacial retreat, despite the
cooling temperatures at that time.
“We must now look more closely at other regions on Earth, such as
the Himalaya, to study the present-day impacts of black carbon on
glaciers in these regions,” said Georg Kaser, a study co-author
from the University of Innsbruck, Austria, and lead author of the
Working Group I Cryosphere chapter of the Intergovernmental Panel
on Climate Change’s upcoming Fifth Assessment Report.
“This study uncovers likely human fingerprints on our changing
environment,” said co-author Waleed Abdalati, director of the
Cooperative Institute for Research and Environmental Sciences at
the University of Colorado Boulder. “It’s a reminder that the
actions we take have far-reaching impacts on the environment in
which we live.”
NASA satellite images and other programs capture the effects of
climate change on the planet and provide data for scientists
worldwide. NASA research and the research of other federal agencies
on climate change are part of a broad U.S. strategy to understand
and ameliorate the effects of climate change.
More
information on NASA’s climate programs is available on the
agency’s website.
Read more:
http://iipdigital.usembassy.gov/st/english/article/2013/09/20130904282232.html#ixzz2eSn8Ns00
