Scandinavian Summer Temperatures from 500 to 2100 AD
Author Information
Author(s): Büntgen Ulf, Raible Christoph C., Frank David, Helama Samuli, Cunningham Laura, Hofer Dominik, Nievergelt Daniel, Verstege Anne, Timonen Mauri, Stenseth Nils Chr., Esper Jan
Primary Institution: Swiss Federal Research Institute WSL
Hypothesis
What are the roles of external forcing and internal variation on climatic changes in Scandinavia?
Conclusion
The study found that internal ocean-atmosphere feedbacks likely influenced Scandinavian temperatures more than external forcing.
Supporting Evidence
- Tree rings dominate millennium-long temperature reconstructions.
- A new reconstruction for the 1483–2006 period correlates at 0.80 with June–August temperatures back to 1860.
- Summer cooling during the early 17th century and peak warming in the 1930s translate into a decadal amplitude of 2.9°C.
- Climate model simulations reveal similar amounts of mid to low frequency variability.
- Projected 21st century warming under the SRES A2 scenario would exceed the reconstructed temperature envelope of the past 1,500 years.
Takeaway
Scientists looked at tree rings to understand how summer temperatures in Scandinavia have changed over the last 1,500 years and found that natural factors played a bigger role than human activities.
Methodology
The study compiled 1,179 series of maximum latewood density measurements from 25 conifer sites in northern Scandinavia and analyzed their climate signal.
Potential Biases
Potential bias due to the reliance on tree-ring data which may not fully represent broader climatic trends.
Limitations
The spatial significance of the reconstruction is limited to the Scandinavian Peninsula and the Baltic Sea.
Statistical Information
P-Value
p<0.001
Statistical Significance
p<0.001
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website