Soot suspect in puzzling mid-1800s Alps glacier retreat

Sep 02, 2013
Mountain peaks in the Bernese Alps protrude above the top of a hazy layer of air. NASA, CIRES and other scientists have uncovered strong evidence that beginning in the 1860s, soot sent into the air by a rapidly industrializing Europe caused the abrupt retreat of mountain glaciers in the European Alps. Credit: Peter Holy

Scientists have uncovered strong evidence that soot, or black carbon, sent into the air by a rapidly industrializing Europe, likely caused the abrupt retreat of mountain glaciers in the European Alps.

The research, published Sept. 2 in the Proceedings of the National Academy of Sciences, may help resolve a longstanding scientific debate about why the Alps glaciers retreated beginning in the 1860s, decades before started rising again.

Thomas Painter, a snow and ice scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., is lead author of the study, and co-authors include Waleed Abdalati, Director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder.

Glacier records in the central European Alps dating back to the 1500s show that between 1860 and 1930, loosely defined as the end of the Little Ice Age in Europe, large valley glaciers in the Alps abruptly retreated by an average of nearly 0.6 mile (1 kilometer). Yet weather in Europe cooled by nearly 1.8 degrees Fahrenheit (1 degree Celsius) during that time. Glaciologists and have struggled to understand the mismatch between the climate and glacier records.

"Something was missing from the equation," Painter said.

To investigate, he and his colleagues turned to history. In the decades following the 1850s, Europe was undergoing a powerful economic and atmospheric transformation spurred by industrialization. Residents, transportation, and perhaps most importantly, industry in Western Europe began burning coal in earnest, spewing huge quantities of and other dark particles into the atmosphere.

When black carbon particles settle on snow, they darken the surface. This melts the snow and exposes the underlying to sunlight and relatively warm air earlier in the year, allowing more and faster melt.

To determine how much black carbon was in the atmosphere and the snow when the Alps glaciers began to retreat, the researchers studied ice cores drilled from high up on several European . By measuring the levels of trapped in the ice core layers and taking into consideration modern observations of the distribution of pollutants in the Alps, they could 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 lower-elevation black carbon. By including this impact, the simulated glacier mass loss and timing finally were consistent with the historic record of glacial retreat, despite the cool temperatures of the time.

"This study uncovers some likely human fingerprints on our changing environment," Abdalati said. "It's a reminder that the actions we take have far-reaching impacts on the environment in which we live."

"We must now look closer at other regions on Earth, such as the Himalaya, to study the present-day impacts of black carbon on glaciers," said Georg Kaser, a study co-author from the University of Innsbruck and lead author of the Working Group I Cryosphere chapter of the Intergovernmental Panel on Climate Change's upcoming Fifth Assessment Report.

Explore further: Strong quake hits east Indonesia; no tsunami threat

More information: End of the Little Ice Age in the Alps forced by industrial black carbon, www.pnas.org/cgi/doi/10.1073/pnas.1302570110

Related Stories

Holocene warming regional

Aug 14, 2012

Research confirms regional — not global — climate change in New Zealand and European glaciers during the preindustrial Holocene

Melting glaciers raise sea level

Nov 14, 2012

Anthropogenic climate change leads to melting glaciers and rising sea level. Between 1902 and 2009, melting glaciers contributed 11 cm to sea level rise. They were therefore the most important cause of sea ...

Austrian glaciers shrink dramatically

Oct 02, 2011

Austria's glaciers shrank dramatically this summer, the most since a record hot period in 2003, principally because of low amounts of snow the preceding winter, scientists said.

Glacial organic matter and carbon cycling

Sep 17, 2012

An international collaboration led by Tom Battin from the Department of Limnology of the University of Vienna unravels the role of Alpine glaciers for carbon cycling. The scientists uncover the unexpected ...

Recommended for you

Strong quake hits east Indonesia; no tsunami threat

17 hours ago

A strong earthquake struck off the coast of eastern Indonesia on Sunday evening, but there were no immediate reports of injuries or damage, and authorities said there was no threat of a tsunami.

Scientists make strides in tsunami warning since 2004

Dec 19, 2014

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

Dec 19, 2014

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.