Persistent link between solar activity and Greenland climate during the Last Glacial Maximum
- Nature Geoscience
- doi:10.1038/ngeo2225
- Received
- Accepted
- Published online
Changes in
solar activity have previously been proposed to cause decadal- to
millennial-scale fluctuations in both the modern and Holocene climates1.
Direct observational records of solar activity, such as sunspot
numbers, exist for only the past few hundred years, so solar variability
for earlier periods is typically reconstructed from measurements of
cosmogenic radionuclides such as 10Be and 14C from ice cores and tree rings2, 3. Here we present a high-resolution 10Be
record from the ice core collected from central Greenland by the
Greenland Ice Core Project (GRIP). The record spans from 22,500 to
10,000 years ago, and is based on new and compiled data4, 5, 6. Using 14C records7, 8 to control for climate-related influences on 10Be
deposition, we reconstruct centennial changes in solar activity. We
find that during the Last Glacial Maximum, solar minima correlate with
more negative δ18O values of ice and are accompanied by
increased snow accumulation and sea-salt input over central Greenland.
We suggest that solar minima could have induced changes in the
stratosphere that favour the development of high-pressure blocking
systems located to the south of Greenland, as has been found in
observations and model simulations for recent climate9, 10.
We conclude that the mechanism behind solar forcing of regional climate
change may have been similar under both modern and Last Glacial Maximum
climate conditions.
