Rapid and comprehensive climate changes have occurred on several occasions back in time. The latest glaciation period – between 115,000 and 11,500 years before the present – caused rapid and extensive fluctuations in the climate. The fluctuations recurred in cycles of about 1500 years and were originally detected when ice cores from Greenland were studied at the beginning of the 1990s. These cycles began with a very rapid temperature rise of as much as 8-16 degrees Celsius in Greenland, over only a few years to some decades.
40,000 years ago
Linda Ampel from the Department of Physical Geography and Quaternary Geology, Stockholm University, has in her doctoral thesis investigated how these rapid fluctuations in the climate affected ecosystems in a region of continental Europe. The study is based on analyses of sediment cores from the infilled basin of a lake called Les Echets in eastern France and focuses on an interval between 40,000 and 16,000 years before the present time.
Diatom analyses, together with further analyses of organic matter and pollen from trees and other plants, show that the ecosystems in the lake and its surroundings underwent extensive changes during the latest ice age as a consequence of these 1500 year cycles. The change in the ecosystems after these recurring warm periods occurred as rapidly as in 50 – 200 years.
- Rapid changes could also occur in future as a consequence of e.g. the global warming, says Linda Ampel.