Alaska glaciers leading to global sea level rise: Study

Alaska's melting glaciers are adding enough water to the Earth's oceans to cover the state of Alaska with a 1-foot thick layer of water every seven years, finds a study.

The study found that climate-related melting is the primary control on mountain glacier loss.

With glacier loss from Alaska unlikely to slow down, this will be a major driver of global sea level change in the coming decades.

"The Alaska region has long been considered a primary player in the global sea level budget, but the exact details on the drivers and mechanisms of Alaska glacier change have been stubbornly elusive," said Chris Larsen, research associate professor with the Geophysical Institute at the University of Alaska Fairbanks.

The team analysed surveys of 116 glaciers in the Alaska region across 19 years to estimate ice loss from melting and iceberg calving.

They collected airborne altimetric liDAR (Light Detection and Ranging) data as part of NASA's Operation IceBridge and integrated the new data with information from the 1990s collected by UAF scientist and pilot Keith Echelmeyer.

"This large dataset of direct observations enabled a much more detailed assessment and attribution of recent glacier change than previously possible," Larsen said.

The study used the airborne observations to compare the changes of two main types of glaciers: those that end on the land and those that end in lakes or the ocean, referred to as calving glaciers.

Using the newly-enabled ability to separate glaciers into different categories using the liDAR data, the researchers made some surprising discoveries.

"This work has important implications for global sea level projections. With improved understanding of the processes responsible for Alaska glacier changes, models of the future response of these glaciers to climate can be improved."

The study is due to be published in Geophysical Research Letters.