The glaciers and thick ice coving sitting on top of Iceland has been compressing the land underneath for thousands of years. Now, as the climate warms the glaciers are receding rapidly. A team of researchers from the University of Arizona (UA) has been using GPS to monitor the shift in Iceland’s land mass as the pressure on it decreases.

The resulting paper, published in Geophysical Research Letters is the first to document the rapid uplift of the Icelandic crust, which coincides with the onset of global warming 30 years ago. According to the study, some areas of south-central Iceland are moving upward at a rate of 1.4 inches per year.

“Our research makes the connection between recent accelerated uplift and the accelerated melting of the Icelandic ice caps,” said first author Kathleen Compton, a UA geosciences doctoral candidate in a statement.

Geologists have long accepted that as glaciers recede the land underneath rises. However, there has been some debate over whether Iceland’s current rebound is due to past deglaciation or modern ice loss. The UA researchers believe that their findings put that debate to rest.

“Iceland is the first place we can say accelerated uplift means accelerated ice mass loss,” said Richard Bennett, a UA associate professor of geosciences.

The researchers used a network of 62 GPS receivers fastened to rocks throughout Iceland. They used this GPS network to “watch” the rocks and calculate the rate at which they were rising, a technique known as geodesy.

Bennett states that there is evidence that during the last time Iceland lost significant glacier mass, about 12 thousand years ago, that volcanic activity increased sharply in some areas of the island. In some areas this increase was thirty times the activity prior to the glacial loss.

There is some concern that the current round of ice loss could trigger increased volcanic activity again. These concerns intensified following the 2010 eruption of Eyjafjallajökull, which shut down air travel in the region and had other economic consequences globally.

The next step for the AU team is to analyze seasonal variations in ice loss. Being able to predict the rate of ice loss and geographic lift could help researchers to anticipate increases in other geological activity.

An increase in volcanic activity in Iceland could have serious repercussions that go far beyond the island nation.

Researchers now believe that an increase in volcanic activity is, at least partially, responsible for the ‘climate change hiatus’, which means that climate change hasn’t been as severe as it would have been otherwise. They also conclude however that this is only a short term effect.

The release of sulfur dioxide by volcanic eruptions can provide a temporary cooling effect as the (So2), which is also the cause of acid rain, blocks sunlight in the atmosphere. However, volcanos also release tremendous amounts of Co2 which means that in the long term they actually intensify the greenhouse effect.

There is also evidence that increasing temperatures lead to an increase in volcanic activity. All of this sets up the potential for a cycle where volcanism causes temperatures to rise which leads to an increase in volcanism.