'Tiger Stripes' Beneath Antarctic Glaciers Slow Sea Level Rise

Ice continues to melt in the Antarctic as temperatures warm and the climate changes. Understanding the physical properties of glaciers in these cold regions, though, is crucial to understand exactly how fast this ice will melt. Now, scientists have uncovered a little bit more about these massive chunks of ice. It turns out that "tiger stripes," narrow strips of dirt and rock, beneath massive Antarctic glaciers create friction zones that slow the flow of ice toward the sea.

Understanding exactly what factors determine the flow of glaciers is an important part of learning about rising sea levels and climate change. When they flow into the ocean, these glaciers can contribute substantially to sea-level rise. In order to learn a bit more about these glaciers, the scientists examined the Pine Island Glacier and the Thwaites Glacier in West Antarctica, which together contribute about 10 percent of the observed sea-level rise over the past 20 years.

Studying the bottom of these glaciers is near impossible due to the inability to see through the mile-and-a-half thick ice. Instead, the scientists employed satellite measurements of the ice velocity and ground-penetrating radar collected from airplane flyovers to detect bedrock and surface topography. Using this data, the researchers created a mathematical model that predicted the stripes beneath the ice.

Similar to the no-slip strips on flooring, these ribs on glaciers provide friction that hinders the ice from slipping along the underlying bed of rock and sediment. These stripes occur in large, slippery regions beneath the glaciers. Since the friction at the interface of the bedrock and glacier ice is a major factor in the speed of the glacier, these stripes are a huge part of understanding future melting.

"The ribs may play an important role in buffering the effects of a warming climate, since they slow the movement of ice that reaches the ocean and contributes to sea-level rise," said Olga Sergienko, one of the researchers, in a news release. "These changes can happen independently of climate change, too."

The findings are published in the journal Science.