NASA Investigate the Role of Soot to Explain Glacial Melting Puzzle

 Alps Glaciers melting due to soot

NASA have recently conducted an extensive investigation into the relationship between industrialization of Europe and the gradual disappearance of mountain glaciers within the Alps, a phenomenon which commenced around the 1860s, a period in time that is believed to have signaled the end of the Little Ice Age. But could the puzzle of glacial melting be explained by the release of soot during the afore-mentioned industrial boom?

The research studies were publicized in the Proceedings of the National Academy of Sciences (PNAS) journal.


Chimney Stacks polluting sootFollowing the 1850s, industrialization was beginning its dominance as many European countries underwent significant economic and environmental changes. Novel technological developments were coming to the fore and manual production methods were being substituted for machine tools. Coal was becoming increasingly popular as one of the primary fuel sources to power industrial equipment and transportation, whilst heating the homes of the masses.

The accelerated use of coal across much of Europe was almost interminable, with the results clear to see; heavily industrial areas churned out substantial volumes of black carbon, casting a thick smog into the atmosphere of many urban regions.

According to a press release from NASA, black carbon can envelope glaciers in a blanket and expedite the speed at which they melt. Black carbon is the greatest sunlight-absorbing particle and can readily melt away the surface layer of snow, covering the glacier. Once this top-layer of “protective” snow is eradicated, the glacier’s ice is revealed to the sun’s rays earlier than normal. Consequently, premature presentation of the glacier to sunlight causes an increase in the rate of glacier melting and, hence, could explain the observation of retreating glaciers during the 1860s.

The Riddle of Retreat

Earth was experiencing a gradual decline in temperature between the 14th and 19th centuries, corresponding with a concomitant growth of mountain glaciers (as would be anticipated); this phase of cooling has been labeled the Little Ice Age.

However, according to NASA, scientists had been alerted to a peculiar anomaly, which they were originally unable to account for. Between 1860 and 1930, the temperature continued to decline. Surprisingly, the glaciers of the Alps did not continue to expand and, in actual fact, began to shrink, retreating by an average of approximately one kilometer.

These observations did not correspond with those collected, within the hundreds of years prior, and seemed to puzzle leading experts in the field of climatology and glaciology.

Thomas Painter, the study’s lead scientist who operates at NASA’s Jet Propulsion Laboratory, ruminated over the perplexing relationship between global temperature and the retreat of glaciers of the Alps. Painter talks about pre-existing notions amongst glaciologists, who had originally considered the mid-1800 retreat to be associated with a “natural climatic shift,” compared to the artificial, human-driven warming that was seen in the 20th century. This is, seemingly, not entirely the case; even though the melting perceived during the mid-1800s was not temperature dependent, it could have been induced by mankind’s pursuit of an industrialized society.

Ice Core Analyses

In an attempt to solve the mystery, once and for all, Painter and his colleagues searched back through time. The research team collected a series of ice cores from a number of mountain glaciers distributed across Europe.

There inside the ice cores, significant quantities of soot had been identified. Armed with this information, the group were then able to approximate the amount of soot that accumulated on the surface layer of glaciers, at much lower elevations.

The team inputted the new data into sophisticated computer models to determine the impact of the soot on glacier retreat. NASA maintain, once the simulation was complete, they were finally able to account for the glacial retreat, despite the lower global temperatures.

According to, other leading experts corroborate Painter’s conclusions. A group of geoscientists, working at Utrecht University in the Netherlands, state they have witnessed a darkening in the surface of glaciers in Switzerland. This group attribute such darkening to settling dust, as opposed to soot particulate, but accept soot’s potential role in the retreat of glaciers.

It’s exciting to see the fruits of such novel research into the mysteries of global warming. Finally, there are some legitimate attempts to fully consolidate our existing knowledge about global warming, whilst filling in the blanks. NASA’s investigation into soot and the puzzle of glacial melting may not fully explain everything just yet, but at least we are one step closer.

By: James Fenner

PNAS Journal Link

NASA JPL Study Website Link

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