When did the Industrial Revolution end

There are around 4, 000 Alpine glaciers of various sizes that are currently under threat from warming temperatures.

During the Little Ice Age, which stretched from the beginning of the 14th Century to around 1850, glaciers thrived in the cool climate and in the mid 19th Century were almost twice as large as they are now, reported.

As Europe became increasingly industrialised the Alpine glaciers suddenly began to retreat but interestingly, average global temperatures did not rise noticeably until the end of the century, causing scientists to look for an explanation why.

Alpine climate records, which are considered to be some of the most reliable in the world, suggest that the bodies of ice should have continued to thrive until around 1910, according to
University of Innsbruck research that was published in journal Proceedings of the National Academy of Sciences1.

Georg Kaser from the university, said: 'Something gnawed on the glaciers that climate records don’t capture.'

Austrian researchers believe the reason for the end of the 'Little Ice Age' in around 1850 could be down to the large amounts of soot being spewed out by Europe's factories and steam engines that settled on glaciers

A sharp drop in the amount of snowfall during winter has previously been blamed for the decline of the glaciers, but the scientist thinks soot is the reason.

He decided to investigate whether soot particles from the burning of coal could explain the decline of the glaciers, after discussing the mystery with Thomas Painter, a snow hydrologist at NASA’s Jet Propulsion Laboratory in California two years ago.

Professor Kaser believes that if soot fell onto the snow and ice of the glaciers, it would have caused them to melt faster as darker surfaces absorb more heat.

His theory is strengthened by historical records that say the air in some Alpine valleys was polluted in the mid 19th Century and 'housewives in Innsbruck refrained from drying laundry outdoors' presumably because soot would dirty the clothes.

Scientists had ruled out a prevalence of soot in the area as a reason for hastening melting glaciers as they thought it would not have been carried high enough to reach the glaciers in large enough quantities.

Dr Kaser's industrial theory is strengthened by historical records that say the air in some Alpine valleys was polluted in the mid 19th Century and 'housewives in Innsbruck (pictured) refrained from drying laundry outdoors' presumably because soot would dirty the clothes

However, Professor Kaiser's team found that in 1860 layers of glacial ice contained large amounts of soot when they looked at ice cores from the Colle Gnifetti glacier at 4, 455 metres above sea level the
Fiescherhorn Glacier at 3, 900 metres in the Bernese Alps.

They calculated the effect the soot would have had on the glaciers using a simplified mass-balance model, to discover the effect of soot explained the glacier retreat.

Andreas Vieli, a glaciologist at the University of Zurich who was not involved in the study, told Nature the modelling could not be more refined and the 'study offers a very elegant and plausible explanation for the glacier conundrum. It appears that in central Europe soot prematurely stopped the Little Ice Age.'

Professor Kaser said global warming only became the primary reason for the retreat of glaciers after 1970 when air quality began to improve.

He warned that if the glaciers continue to melt at the same rate as the past 30 years, they could disappear by the close of the century.