Watt’s Up With That reports new research on remote Siberian Lake El’gygytgyn with sedimentary layers which record climate for 2.8 million years. The climate reconstructions correlate with Arctic and Antarctic records. WUWT states in the article Claim: Fates of polar ice sheets appear to be linked:
Lake E was formed 3.6 million years ago when a huge meteorite hit Earth, leaving an 11-mile-wide crater. It’s been collecting layers of sediment ever since.
The lake is of interest to scientists because it has never been covered by glaciers. That has allowed the uninterrupted build-up of sediment at the bottom of the lake, recording hitherto undiscovered information on climate change.
Cores from Lake E go far back in time, almost 30 times farther than Greenland ice cores covering the past 110,000 years.
The sediment cores from Lake El’gygytgyn reflect the climate and environmental history of the Arctic with great sensitivity, say Brigham-Grette and colleagues.
The physical, chemical and biological properties of Lake E’s sediments match the known global glacial/interglacial pattern of the ice ages.
Some warm phases are exceptional, however, marked by extraordinarily high biological activity in the lake, well above that of “regular” climate cycles.
To quantify the climate differences, the scientists studied four warm phases in detail: the two youngest, called “normal” interglacials, from 12,000 years and 125,000 years ago; and two older phases, called “super” interglacials, from 400,000 and 1.1 million years ago.
According to climate reconstructions based on pollen found in sediment cores, summer temperatures and annual precipitation during the super interglacials were about 4 to 5 degrees C warmer, and about 12 inches wetter, than during normal interglacials.
I have added a comment to the post:
Given that there is a 400,000 year Milankovitch cycle also (Earth orbital eccentricity period), the super inter glacials at 0.4 and 1.1 m years ago would indicate that this interglacial could be expected to be a super inter glacial also.
This is very important, because it is evidence that we might expect the present interglacial to be an exceptionally warm one.