 The study quantifies the spatial and temporal variability of carbon sources and sinks to predict future levels of atmospheric carbon dioxide and verify current emission agreements, finding large carbon sinks in the southeastern U.S. that may be impacted by extreme land use disturbance events due to mountaintop coal mining. The study applies ecosystem modelling and field experiment data to quantify the potential impact of future mountaintop coal mining on the carbon budget of the southern Appalachian forest region, finding that the forests switch from a net carbon sink to a net carbon source by year 2025-33 with a significant loss in terrestrial carbon stocks. The study also suggests that accounting for mountaintop coal mining in bottom-up inventories may be critical for regional carbon budgets. This article was authored by J. Eliot Campbell, James F. Fox, and Peter M. Acton.