ABACUS (Arctic Biosphere Atmosphere Coupling at Multiple Scales) is funded by a grant (NE/D005795/1) from the Natural Environment Research Council (NERC) International Polar Year (IPY) Programme. The ABACUS research project is a major, linked programme of plant and soil studies, atmospheric measurements, aircraft and satellite observations, and modelling, to improve our understanding of the response of the arctic terrestrial biosphere to climate change. The data collected includes root measurements and isotope ratios of plants, CH4 emissions of soils, measurements of Carbon and water exchanges between soils/vegetation and the atmosphere at fine scales (resolution of ~1m), and at scales of ~100m, records of snow depth, soil moisture and climate, and aircraft images of the land surface and profiles of CH4.