Swiss Glaciers Expose Earlier Warm Periods
Receding glaciers in the Swiss Alps are exposing evidence of earlier warm Holocene periods. Researchers are discovering that green forests once existed under the ice and that the Alps were mostly greener than today. New findings obtained by a Swiss glaciologist cast more doubt on today’s global warming hypotheses.
The following is a summary essay of the report that appeared in the Swiss news journal Die Weltwoche by Alex Reichmuth http://www.weltwoche.ch/ausgaben/2010-15/artikel-2010-15-gletscherforschung-die-zeugen-frueheren-klimawandels.html
Christian Schlüchter, Professor of Geology, and his team of researchers are studying remnants of ancient trees and peat that have been exposed by melting glaciers high in the Swiss Alps. At first sight, these pieces of wood may not look spectacular, but they are up to 10,000 years old and have a story to tell.
These tree remnants include complete tree trunks that were scraped and twisted by the massive ice sheets that once covered them. Over time these chunks of wood were transported by the glaciers partway down the Alps, and it was not exactly sure from what elevation they originated. But the wood chunks and peat prove one thing: Today, where one now only finds bare rock and gravel, and even where there is still ice, trees once grew there thousands of years ago.
In fact, entire forests must have existed there because in some places the wood remnants were found in piles. By looking at flow and glacial movement patterns of the individual glaciers, Prof Schlüchter and his team have been able to reconstruct the path the wood chunks and peat must have taken, and thus they were able to pinpoint their original location of growth. Schlüchter knows quite precisely when the trees grew and from where the peat originated.
Examining carbon isotopes in a high-tech laboratory, he has been able to determine the exact age of the uncovered artefacts and precisely when and where the trees grew. The information allows him to piece together a pretty good picture of the glacial history in the Alps since the end of the last ice age. Some trees at very high altitudes even lived 600 years. Schlüchter says the equilibrium line that is the boundary between the feed and depletion zones of the glacier was as much as 300 meters (1000 ft) higher in elevation than today.
Why the glaciers melted over the last several thousands years is not clear. Clearly periods with less ice correspond to periods of high solar activity. That is shown by measurements of nuclides in the soil. Currently Schlüchter and his team are studying the wood remnants to reconstruct precipitation and temperature going back thousands of years, which will allow them to learn more about the climate back when the trees were growing.
It is known 2000 years ago, during the Roman Empire, that the glaciers in the Alps had receded considerably. The Romans often crossed the Alps unhindered. Schlüchter believes that it was as much as 1°C warmer back then. Whether it was just as warm back in during the Medieval period, he cannot say with certainty. Schlüchter’s findings show that today’s receding glaciers in the Alps is nothing unusual and is completely normal. Today’s temperatures are also not unusual.
When asked if his findings contradict today’s claims of modern climate change, Professor Schlüchter says,”Much is driven by the sun”. When asked about what his colleagues think of his findings, he declines to respond. Other scientists refute Schlüchter’s findings and claim that the glacial melt of the last 20 years is unprecedented. But Schlüchter claims the glaciers started melting in the 1850s – long before industrialisation really took hold.
Schlüchter also dismisses taking the trend over last 150 years and linearly projecting it into the future: “That’s nonsense”. Nobody knows. For example, glaciers grew in the 1980s and no one can explain why. Still, other established glaciologists claim the glaciers in the Alps will all but disappear by 2100. But Schlüchter differs, “Glacial behaviour is complex. I view their projections as being not very scientific”. Prof Schlüchter’s website:Glaciers