To summarize:
Increased solar activity cooled Greenland from the 1950's to the early 1990's due to a decreased Gulf Stream current.
Decreased solar activity warmed Greenland from the 1990's to the present due to an increased Gulf Stream current.
However, unstated, global warming was supposed to decrease the Gulf Stream current. We have been having global warming since 1950's. Therefore, we should be having cooling in Greenland and increased ice. Therefore, the warming of Greenland over the last 2 decades is actually evidence that global warming has not been happening.
However:
Another recent study by [Penn State Professor Michael] Mann and his colleagues proposed that trapped greenhouse gases from fossil fuel burning caused warming across the Northern Hemisphere and triggered an increase in ice melt. This led to the slowdown in ocean circulation and a cooler Greenland.So warming causes slowdown, but then so does decreased solar activity which causes cooling.
The increased flow of warm water and air to Greenland due to decreased solar activity will cause increase melting of Greenland's ice.
However, unstated, decreased solar activity is correlated with decreased world-wide temperatures, which should increase glacial ice in other places.
On the other hand, the Medieval warm period caused ice to melt in Greenland (which is why it is called "Greenland"). And the Little Ice Age (1300 to 1850) caused Greenland to ice up again, driving the Vikings to abandon their settlements there.
The Little Ice Age is correlated with decreased solar activity, the Maunder Minimum.
So we have both cooling periods and warming periods correlated with both warming and cooling episodes in Greenland.
I would guess that there may actually be a way to reconcile all this, and the researchers do propose a test to see if their hypothesis works out.
Starting around 2025, temperatures in Greenland could increase more than anticipated and the island's ice sheet could melt faster than projected,
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