http://www.volcano.si.edu/world/largeeruptions.cfm

The importance of considering only large volcanoes is that they are studied in modern times, and therefore the data is not plagued with problems related to limited reporting in the past.

The presumed increase in volcanic activity points to increased motion in tectonic plates. It seems more than a coincidence that this activity is occurring just as the next ice age is scheduled to begin. The meaning however is not totally clear. A number of questions are raised.

The first thing it means is that humans producing carbon dioxide is not the only possible explanation for global warming, as propagandists often claim. There are major geological and cosmological forces at work producing change on the planet all the time.

A question which is often raised is whether increased volcanic activity on the ocean floor could be the cause of oceans heating. It is a very realistic explanation and in line with existing evidence. Limited measurements have shown some unexpected heat in the deep oceans. Deep Ocean Heat Measured

However, it is possible that increased tectonic activity is only one manifestation of changing forces acting upon the planet. The most likely cause of such changing forces is the cyclic nature of the earth's orbital rotation which has a 100 thousand year tilt corresponding with the 100 thousand year intervals of ice age cycles.