How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic


A Thousand-Year Pollen Record of Environmental Change in the Northern Altai Mountain Region of Southern Siberia
Reference
Andreev, A.A., Pierau, R., Kalugin, I.A., Daryin, A.V., Smolyaninova, L.G. and Diekmann, B. 2007. Environmental changes in the northern Altai during the last millennium documented in Lake Teletskoye pollen record. Quaternary Research 67: 394-399.

What was done
Working with a sediment core extracted from the central and deepest part of Lake Teletskoye in the northeastern part of the Altai Mountains in southern Siberia (5143'N, 8739'E), the authors analyzed pollen and charcoal stratigraphy to develop "the first detailed climate and vegetation reconstruction for the last millennium in the northern Altai Mountains."

What was learned
Quoting the six researchers, "dense Siberian pine forest dominated the area around the lake at least since ca. AD 1020," when they say "climate conditions were similar to modern [our italics]." Then, "between AD 1100 and 1200, a short dry period with increased fire activity occurred," and "around AD 1200, climate became more humid with the temperatures probably higher than today [our italics]." This period of rather stable climate, "possibly reflecting [the] Medieval Warm Epoch, lasted until AD 1410," after which "slightly drier climate conditions occurred between AD 1410 and 1560." Thereafter, they say "a subsequent period with colder and more arid climate conditions between AD 1560 and 1820 is well correlated with the Little Ice Age," after which they found evidence for a climate warming they "inferred from the uppermost pollen spectra, accumulated after AD 1840," which was "consistent with the instrumental data" of the modern period.

What it means
It is clear from Andreev et al.'s findings that the Altai Mountain region of southern Siberia displays the characteristic millennial-scale cycling of climate from Medieval Warm Period to Little Ice Age to Current Warm Period conditions that is characteristic of most of the rest of the world (see Climate Oscillations (Millennial Variability) in our Subject Index). In addition, it is of interest to note that from approximately AD 1200 to 1410, they conclude that temperatures in the region of their study were "probably higher than today," providing yet another example of times and places when low-CO2 Medieval Warm Period temperatures were likely higher than high-CO2 Current Warm Period temperatures. For more on this eye-opening subject, see our Medieval Warm Period Project.

Reviewed 15 August 2007