Geoscience Reference
In-Depth Information
Figure 9-12.
Summary chart of main indicators and trends for latest Pleistocene and Holocene climate in northern
Europe and Greenland. Asterisks (*) indicate the 8.2 ka cooling event and the Little Ice Age. Dates given in calendar
years ago. Compiled from many sources; adapted from Seppä, H., Birks, J.B., Bjune, A.E. and Nesje, A. 2010.
Current continental palaeoclimatic research in the Nordic region (100 years since Gunnar Andersson
1909) - Introduction.
Boreas
39/4, p. 649-654., Fig. 1.
These long-term trends were interrupted by
“abrupt events” during which the climate became
markedly colder, namely the cooling at 8200
years ago (8.2 ka event) and the Little Ice Age
(
c.
800 to 100 years ago). Changes in wetlands
and vegetation generally were caused by climatic
l uctuations. In the subarctic tundra region of
northwestern Finland, for example, peatlands ini-
tiated and expanded rapidly in the early Holocene,
then expansion slowed to a modest pace in the
mid-Holocene (Weckström, Seppä and Korhola
2010). Rapid expansion again took place in the
late Holocene (4000-3000 years ago), then grad-
ually slowed toward present rates. This scenario
follows the overall trends for Holocene climate
change seen throughout Fennoscandia.
Wetland and upland vegetation did not
depend solely on climatic conditions, however.
When attempting to interpret ancient vegeta-
tion, one should recognize that “no similar plant
communities exist today,” as Iversen (1973, p.
26) emphasized. The vegetation succession that
took place in Fennoscandia during the Holocene
was driven by changes in climate, but also
depended on several other factors, such as plant
migration rates, species competition for light,
changes in soil quality, and human impact.
During the late-glacial phase, for instance,
