Arctic Greening Thaws Permafrost, Boosts Runoff

Study finds shrubs trap snow, creating permanently thawed zones that destroy permafrost and create pathways for increased water and carbon flow.

A new collaborative study has investigated Arctic shrub-snow interactions to obtain a better understanding of the far north's tundra and vast permafrost system.  Incorporating extensive in situ observations, Los Alamos National Laboratory scientists tested their theories with a novel 3D computer model and confirmed that shrubs can lead to significant degradation of the permafrost layer that has remained frozen for tens of thousands of years.  These interactions are driving increases in discharges of fresh water into rivers, lakes, and oceans.

"The Arctic is actively greening, and shrubs are flourishing across the tundra.  As insulating snow accumulates atop tall shrubs, it boosts significant ground warming," said Cathy Wilson, Los Alamos scientist on the project.  "If the trend of increasing vegetation across the Arctic continues, we're likely to see a strong increase in permafrost degradation."

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