CR 48:5-11 (2011) - DOI: https://doi.org/10.3354/cr00873

Contribution to the CR Special: 'Environmental change and socio-economic response in the Baltic region'

Current global warming appears anomalous in relation to the climate of the last 20000 years

Svante Björck*

Department of Earth and Ecosystem Sciences, Division of Geology, Quaternary Sciences, Lund University, Sölveg. 12,

223 62 Lund, Sweden

ABSTRACT: To distinguish between natural and anthropogenic forcing, the supposedly ongoing global warming needs to be put in a longer, geological perspective. When the last ca. 20000 yr of climate development is reviewed, including the climatically dramatic period when the Last Ice Age ended, the Last Termination, it appears that the last centuries of globally rising temperatures should be regarded as an anomaly. Other, often synchronous climate events are not expressed in a globally consistent way, but rather are the expression of the complexities of the climate system. Due to the often poor precision in the dating of older proxy records, such a statement will obviously be met with some opposition. However, as long as no globally consistent climate event prior to today’s global warming has been clearly documented, and considering that climate trends during the last millennia in different parts of the world have, in the last century or so, changed direction into a globally warming trend, we ought to regard the ongoing changes as anomalies, triggered by anthropogenically forced alterations of the carbon cycle in the general global environment.

KEY WORDS: Global warming · Long-term perspective · Climate anomaly