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Highlights

Since 1989, the U.S. Global Change Research Program (USGCRP) has submitted annual reports to Congress called Our Changing Planet. The reports describe the status of USGCRP research activities, provide progress updates, and document recent accomplishments.

In particular, Our Changing Planet highlights progress and accomplishments in interagency activities. These highlights represent the broad spectrum of USGCRP activities that extend from Earth system observations, modeling, and fundamental research through synthesis and assessment, decision support, education, and public engagement.

Carbon Cycle, Arctic

Scientists investigate the effects of carbon emissions from thawing permafrost soils

Methane emitted from thawing permafrost below an Arctic thermokarst lake is trapped in bubbles of many different sizes and shapes as the ice grows during the winter.
Long-frozen northern soils known as permafrost contain one of the world’s largest stores of organic carbon. This reservoir is stable while soils are frozen, but as permafrost thaws, decomposition of biomass by microbes produces the heat-trapping gases carbon dioxide and methane, returning soil carbon to the atmosphere where it contributes to climate change. Permafrost carbon stores are expected to be increasingly vulnerable to decomposition as the climate continues to change, leading to a feedback cycle of further warming and permafrost thaw.[1]...
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Observations, Modeling, Ecosystems & Biodiversity, Carbon Cycle, Arctic

Understanding carbon cycling in Arctic ecosystems

Map shows the average active layer thickness (ALT) at the end of the growing season for the Barrow, Alaska region that contains the NGEE Arctic study site.

Scientists are gaining new understanding of processes that control greenhouse gas emissions from Arctic permafrost, a potential driver of significant future warming.

Rapid warming in the Arctic is causing carbon-rich soils known as permafrost, previously frozen for millennia, to thaw. As thawing soils decompose, the greenhouse gases carbon dioxide and methane are released into the atmosphere in varying proportions depending on the conditions under which decomposition occurs. Permafrost emissions could contribute significantly to future warming...

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Modeling, Carbon Cycle, Arctic

Modeling Permafrost Response to Climate Change

Modeling Permafrost Response to Climate Change

Vast quantities of carbon—twice the size of the current amount in the atmosphere—are stored in frozen permafrost soils in Arctic regions. The Arctic climate is warming much more rapidly than the global average, leaving these carbon pools highly vulnerable to release into the atmosphere as carbon dioxide and methane as soils thaw and decompose, leading to a feedback cycle of further warming and increasing carbon release. The potential for these carbon stocks to increase global-warming rates, and the rapid changes already observed in the permafrost region, have captured the attention of...

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Ecosystems & Biodiversity, Carbon Cycle, Arctic

Improving Predictions of Changing Arctic Ecosystems

Improving Predictions of Changing Arctic Ecosystems

A key challenge for Earth System Models is accurately representing land surface and subsurface processes and their complex interactions in a warming climate. This is true for ecosystems across the globe, but particularly critical for Arctic ecosystems, which are projected to warm at a rate twice that of the global average by the end of the 21st century. The Next-Generation Ecosystem Experiments in the Arctic (NGEE-Arctic) project is addressing this challenge by integrating process studies, ecosystem observations, and computational...

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Observations, Carbon Cycle, Arctic

Tracking Methane Emissions from Arctic Tundra

Tracking Methane Emissions from Arctic Tundra

The Arctic tundra is a cold, desert-like biome, with a layer of permanently frozen soil and organic matter below the surface containing vast stocks of carbon. As Arctic tundra soils warm in response to climate change, methane emissions from decomposing organic material could increase dramatically, representing a potentially significant positive feedback on climate warming. However, seasonal and climatic influences on methane emissions from these systems are not well understood outside of the summer months, representing a major uncertainty for the Arctic methane budget. To help address a...

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