There is a strong positive correlation between the melting of ice and the acceleration of volcanic activity. Since glaciers and ice sheets on volcanoes are melting rapidly, Tuffen (2010) concludes that there will be an increase in volcanic eruptions and hazards in the 21st century.
Rapid thinning and recession of ice has been observed on many active and dormant volcanoes. The current ice recession is caused primarily by increased global temperatures, reduced precipitation and regional geothermal and volcanic pressures. Similar ice recessions in the past have been associated with massive increases in volcanic activity. In the past, the thinning of ice has resulted in more explosive eruptions and the collapse of volcano edifices. While it is difficult to quantitatively compare the current ice recession to the past ones, Tuffen is certain that the frequency—and possibly the magnitude—of volcanic eruptions will increase significantly in the 21st century. —Sachi Singh
Tuffen, H. 2010. How will melting of ice affect volcanic hazards in the 21st century? Philosophical Transactions of the Royal Society A 369, 2535–2558.
There are several hazards associated with thinning ice: any disturbance caused by volcanic eruptions disrupts the stability of the ice sheets and causes large floods and destructive mudflows down the slopes of the volcanoes. The meltwater, which is formed as a consequence of the melting ice, can outwash plains, collapse dams and causes massive devastation of life and property. The thinning of ice can reduce sub-glacial eruptions, which leads to more explosive eruptions with increased ashfall and pyroclastic debris. The thinning of ice causes large scale destruction, but also causes an increase in the frequency of volcanic eruptions. The most dramatic example of the correlation between the thinning of ice and increased volcanic activity was observed in Iceland, where the unloading of ice caused a decompression which lead to a greater degree and depth range of mantle melting; consequently, there was a huge increase in the rate of magma eruption on the individual volcanic systems 1.5 ka after the deglaciation of the area. This indicates that Iceland volcanism responds to the change in ice thickness very quickly. While these trends have been observed in east California and western Europe, there is little analysis on whether the magnitude of the eruptions increase during deglaciation events. To further explore this, Tuffen compared the inferred rates of melting during the past glaciation events with the current rates of melting; while he could not conclusively construct the rates of ice thinning during the last glaciation due to different local geographic and geothermal discrepancies, he did observe that the current ice recession is considerably shorter that ones in the past. In order to shine more light on the relationship between climate change and volcanism, Tuffen suggests that future research should be conducted to understand the time scale of the volcano’s response to ice thinning and the broader feedbacks between volcanism and climate change.