Montana glaciers affect rising seas researcher says

What does the rise in sea level have to do with Montana? 

Most Montanans would say nothing, but Professor Joel Harper, a glaciologist at the University of Montana, knows that there is a connection.

According to Harper, the melting glaciers in the Northern Rocky Mountains - like the ones in Glacier National Park - not only provide an enormous amount of water during Montana’s dry season, but also affect the level of sea rise, which is inevitable due to climate change. 

Harper said Montana’s glaciers, part of 300,000 or so glaciers around the world, are responsible for 60 percent of any sea level rise.

Harper said most people don’t understand that floating sea ice, like the ice shelves that break off from Antarctica and Greenland, doesn’t affect sea level rise. 

“That ice is already in the ocean, and the water is already displaced,” Harper said.  “It’s the ice that’s sitting on land that changes the sea level.”

Water from inland glaciers ultimately winds up in the ocean. Melt water from the surface of glaciers with outlets to the ocean causes ice motion —referred to as “ice dynamics.” This lubrication increases the glacial rate of speed to the sea, where they break off - a process called “calving” - and adds to ocean ice, raising the sea level.

The term “ice dynamics” is a “wildcard,” Harper said, because the behaviors of the ice sheets are unpredictable. 

“Sea level is going to rise. It’s going to happen,” Harper said. 

The question is by how much.

There have been a lot of projections, including one recently from Al Gore’s group, the Intergovernmental Panel on Climate Change, a group of 600 scientists who projected a sea level rise of 18 to 60 centimeters - 7.2 to 24 inches - by 2100.

Harper’s team, which spent the summer in Greenland studying glaciers, returned to publish an article in Science Magazine that contradicts this projection. 

“We’re saying 80 centimeters is plausible, but two meters will be within the realm of what’s possible,” Harper said.

Harper, who has been inundated with calls from around the world about his study, said the numbers his team published are higher than the panel’s, but that they ruled out a lot of projections that were more outrageous.

“We bracketed the results of current projections by including ice dynamics,” Harper said.

The numbers matter, Harper said, because sociologists predict that a sea level rise of even one meter could displace 148,000,000 people. Most of those will be from Asia, but sea level rise is an economic issue that will affect Montanans because most preparations will be made with federal monies, to which Montanans will contribute, according to Harper.

Harper said the field of glaciology is a growing field, as studying the changes in glaciers is an indicator of global climate change. Having Glacier National Park nearby gives students an opportunity to learn the skills they need to study glaciers worldwide. 

“It’s like having our own little test tube,” Harper said.

deborah.tanner@umontana.edu