“Fluctuations in climate were due in large part to periodic changes in the Earth’s orbit parameters.”
“Data again confirms what Robert has said, that an ice age can arrive within a decade,” says reader George Martinez.
Deposits on the bed of Lake Van provide unique insights into the last 600,000 years. Image courtesy Thomas Litt/Uni Bonn.
When researchers drilled through the sediments of Lake Van (Eastern Turkey) in 2010, the lighter-colored, lime-containing summer layers were clearly distinguishable from the darker, clay-rich winter layers — also called varves.
Climate conditions, earthquakes and volcanic eruptions of the past 600,000 years can be read in outstanding quality from the cores.
“The results show that the climate over the past hundred thousand years has been a roller coaster. Within just a few decades, the climate could tip from an ice age into a warm period,” says Doctor Thomas Litt of the University of Bonn’s Steinmann Institute and spokesman for the PALEOVAN international consortium of researchers.
The sediments reveal six cycles of cold and warm periods
Scientists found evidence for a total of six cycles of warm and cold periods in the sediments of Lake Van.
Based on the type of pollen and the age, the scientists were able to determine when oak forests typical of warm periods grew around Lake Van and when ice-age steppe made up of grasses, mugwort and goosefoot surrounded the lake.
“Fluctuations in climate were due in large part to periodic changes in the Earth’s orbit parameters”
These analyses enable the team of researchers to read the varves of Lake Van like thousands of pages of an archive. With these data, the team was able to demonstrate that fluctuations in climate were due in large part to periodic changes in the Earth’s orbit parameters and the commensurate changes in solar insolation levels.
Please note that there is no mention of humans triggering any of these climate fluctuations, either warmer or colder.
See entire article, entitled “Climate capers of the past 600,000 years”
http://www.terradaily.com/reports/Climate_capers_of_the_past_600000_years_999.html
Thanks to George Martinez for this link