Solar forcing as an important trigger for West Greenland sea-ice variability over the last millennium

H/T to Andrew for alerting me to this new paper published in Quaternary Science Reviews.

From the paper:

Fig. 5. Reconstructed sea-ice concentrations from core GA306-GC4 compared to the 14C production rate corrected for the fossil fuel (Suess) effect for the period from 1850 to 1950 AD (Muscheler et al., 2007). (a) The direct comparison of sea-ice concentration (blue) and 14C production rate (red), as well as with DTSI (orange; difference of total solar irradiance from 1365.57 W/m2 ) (Steinhilber et al., 2012)

To investigate the feedback processes linking solar activity and sea-ice cover, we used the coupled climate model COSMOS, which indicates that a decrease in solar radiation results in increased sea-ice cover (Fig. 7a) and decreased sea-surface temperature (Fig. 7b). A strong negative correlation between sea-ice variability and solar forcing is observed along the eastern and southwestern coast of Greenland and in the Arctic Ocean, indicating that in this model solar variability is critical for simulating changes in local sea-ice production. A small change in incoming shortwave radiation, and associated ice-albedo effects, resulted in a large response of local ice formation, according to ‘bottom-up’ (solar heating of the sea surface) mechanisms (Gray et al., 2010; Hunke et al., 2010).

Researchers find 200-year lag between climate events in Greenland and Antarctica

One of Greenland’s islands [credit: Wikipedia]

Science Daily reports on recent research by Oregon State University (H/T The Hockeyshtick):
A new study using evidence from a highly detailed ice core from West Antarctica shows a consistent link between abrupt temperature changes on Greenland and Antarctica during the last ice age, giving scientists a clearer picture of the link between climate in the northern and southern hemispheres.

Greenland climate during the last ice age was very unstable, the researchers say, characterized by a number of large, abrupt changes in mean annual temperature that each occurred within several decades. These so-called “Dansgaard-Oeschger events” took place every few thousand years during the last ice age. Temperature changes in Antarctica showed an opposite pattern, with Antarctica cooling when Greenland was warm, and vice versa.

In this study funded by the National Science Foundation and published this week in the journal Nature, the researchers discovered that the abrupt climates changes show up first in Greenland, with the response to the Antarctic climate delayed by about 200 years. The researchers documented 18 abrupt climate events during the past 68,000 years.