Iceland is rising as global warming melts its glaciers

The surface level of Iceland is rising by as much as 1.4 inches per year, and scientists are linking the problem to glacial melting driven by global warming over the past 30 years.

A University of Arizona-led team has established the connection between the rebounding of the Earth's crust under Iceland to global warming, which melts the island's great ice caps.

Geologists have found that, as glaciers melt, the Earth rebounds upwards under the decreased weight above.

But whether this was due to past deglaciation or modern ice loss has been an open question until now, says co-author Richard Bennett, a UA associate professor of geosciences.

"Iceland is the first place [where] we can say accelerated uplift means accelerated ice mass loss" says Bennett.

Using a network of 62 global positioning satellite receivers fastened to rocks throughout Iceland, the team watched how the rocks moved and calculated the distance travelled since 1995.

The geodesy network was being used to track geological activity such as earthquakes and volcanic eruptions. But in 2013, Bennett noticed one of the long-running stations in the centre of the country was rebounding at an accelerated rate.

This led the team to check at other stations where they noticed similar movement.

After analysing years of signals from the entire network they found the fastest uplift was in the region between several large ice caps. The rate of uplift slowed the farther the receiver was from the ice cap region.

Temperature records for Iceland, some of which go back to the 1800s, show temperatures increasing since 1980.

Mathematical models showed that the same ice loss every year did not lead to such an uplift, but a speeding rate of glacier melt could result in the rise

The onset of rising temperatures and the loss of ice corresponded tightly with estimates of when uplift began. "I was surprised how well everything lined up," first author Kathleen Compton, a UA geosciences doctoral candidate said.

The findings will be published in an upcoming issue of Geophysical Research Letters.

Estimating ice loss however is going to be laborious and difficult.

The team plans to analyse the uplift data to reveal the seasonal variation as the ice caps grow during the winter snow season and melt during the summer.

Studies have estimated the Icelandic crust's rebound from ice loss could increase the frequency of volcanic eruptions such as the 2010 eruption of Eyjafjallajökull.

The Greenland ice sheet has shed about 277 cubic kilometres of ice per year from 2003-09, enough to raise oceans by about 0.68 millimetres per year while the melt rate of glaciers in west Antarctica has tripled in the last decade.

Rise of sea levels and extreme weather events are among the immediate impacts of global warming brought about by the burning of fossil fuels.