||The Arctic is undergoing a system-wide reorganization in response to an altered climate. The mechanisms responsible for this change have been unpredictable and difficult to isolate due to a large number of interactions among individual components of the system. The Next-Generation Ecosystem Experiments (NGEE) project will quantify the complex physical, chemical, and biological behavior of terrestrial ecosystems in Alaska. The project will focus on interactions that drive ecosystem-climate feedbacks through greenhouse gas fluxes and changes in surface energy balance associated with thawing permafrost and threshold-dominated permafrost degradation and thermokarst formation. Research sites will be located along a bio-climatic gradient that spans tundra and shrub-tundra transition zones on the North Slope and Seward Peninsula. The ultimate deliverable of the NGEE project is a high-resolution terrestrial system model that is able to simulate coupled thermal, hydrological, geomorphic, biogeochemical, and vegetation processes as needed to predict the evolution of a warming Arctic landscape and its feedback to the global climate system. This vision includes field observations, laboratory experiments, and modeling of critical and interrelated water, nitrogen, carbon, and energy dynamics, and important interactions from the molecular to the landscape scale that drive feedbacks to the climate system.