Scientists study shrinking glacier
Mauri Pelto digs his boots into the steep icy slope. He is on Mount Baker. It is in Washington State. He watches as streams of water flow off the thick mass of bare, bluish ice. The water carves up-and-down paths in the face of the glacier as it rushes downstream. It happens every 20 yards.
What little snow from last winter is already gone. Ice is melting off the glacier. It is melting at a rate of nearly three inches a day this summer, he said.
"At the rate it is losing mass, it won't make it 50 years," said Pelto. He is a glaciologist. He returned to the area in August. It was his 32nd year returning. He went to study glaciers in the North Cascades range. "This is a dying glacier," he said.
Glaciers on Mount Baker and other mountains in the North Cascades are thinning. That means they are getting smaller. They are melting away. Seven have disappeared over the past 30 years. The glaciers in the range have lost about one-fifth of their volume.
The shrinking glaciers here copy what is happening around the U.S. and worldwide. As the planet warms, glaciers are losing size. Some are fading faster than others.
Two of the largest glaciers in Yosemite National Park in California have retreated over the past century. They have lost about two-thirds of their surface areas.
In Alaska they did a study of 116 glaciers. It was estimated that they have lost about 75 billion metric tons of ice. That is every year from 1994 to 2013.
Scientists in Montana are seeing the impacts too. They see it in a higher stream temperature. And also in changes to high-elevation ecosystems.
In 1850, there were 150 glaciers at Glacier National Park. Now there are 25.
"These glaciers are rapidly disappearing. From a geological standpoint." said Dan Fagre. He is a research ecologist. He works with U.S. Geological Survey. He is stationed in Glacier National Park. "They are so small and vulnerable that they could be gone in a matter of decades."
Glaciers are thick masses of collected snow. They form into ice and move. Glaciers are important signs of climate change. That is because they are driven by precipitation and temperature.
Mount Baker is a volcanic peak about 125 miles northwest of Seattle. Its glaciers provide an important water source. The water is needed for farming. Cities and tribes need it during the late summer. The icy glacial melt keeps streams cool for fish. It also refills rivers. The melt comes during a time of year when the rivers typically run low.
The Nooksack Indian tribe has relied for hundreds of years on salmon runs in the glacier-fed Nooksack River. That way of life is at risk. Without that glacial runoff, rivers will dry up more quickly. They also will warm up faster. It will make it harder for salmon to spawn or move to the ocean.
"Climate change will impact the ability of tribal members to harvest fish in the future," said Oliver Grah. He is water resources manager. He works for the tribe. The tribe has teamed up with Pelto. They want to know how glacier runoff will affect the river's fish habitat and repair planning.
Grah and colleague Jezra Beaulieu recently hiked 5 miles into the Sholes Glacier. They wanted to study how climate change will affect the timing and size of stream flow in the river. It is their fifth field trip to the glacier this summer. They are amazed each time they go. They see how fast the snow and ice are melting.
Grah strings a measuring tape across the stream. Then he wades in shin-deep. He measures the depth of the water streaming from the toe of the glacier. He calls out numbers. Beaulieu records them. They are trying to figure out how much flow and sediment is coming from the glacier.
"This is a frozen reservoir that yields water all summer long," said Pelto. He is a professor of environmental sciences. He works at Nichols College. It is located in Dudley, Massachusetts. "So you take this away and what are you going to replace it with?"
The tribe also is working with Western Washington University. The college is using data collected in the field. That information is used to model what the stream flow will be like in the future.
"The late summer flows controlled by melting glaciers are predicted to decrease as the glaciers get smaller and smaller," said Robert Mitchell. He is a geology professor. He works at Western Washington University.
This year Washington state had a record low snowpack. They had warmer temperatures that have made it one of the worst Pelto has seen. He has been studying the glaciers for more than 30 years.
"They are losing volume at a faster rate than ever before," Pelto said. "If you cannot sustain a glacier at a place like this in the Lower 48 states, there is no hope."
CRITICAL THINKING QUESTION
Why does Mauri Pelto describe this as a "dying glacier?"
Write your answers in the comments section below