Soil is one of the largest reservoirs of carbon, and could potentially buffer climate change by storing some of the extra carbon dioxide humans are releasing to the atmosphere. Yet, the stability of soil carbon is unsure, and its sensitivity to environmental change poorly understood at broad, general scales, despite decades of global change research projects. One critical problem is that the soil carbon pool is large and changes very slowly, making it hard to determine whether changes observed in experiments are real or are “noise” caused by plot-to-plot variation. At at the same time, small changes are important, and could indicate substantial impacts on the future capacity of the biosphere to store carbon. The research we propose holds promise for surmounting this problem, by synthesizing results from multiple experiments using “metaanalysis” (quantitative data synthesis), increasing our ability to detect whether changes are real and whether they are general across ecosystems and environments. Another critical challenge is how carbon storage in ecosystems is influenced by other essential resources, and particularly nutrients, which through various pathways could amplify or dampen changes in carbon storage. Earth system models have identified these interactions as crucial, but disagree about how large they are, and even in which direction they operate. The research we propose combines metaanalysis with theory of element cycling to examine these questions using data from real, on-theground, experiments conducted over the past several decades. Our proposed approach extends beyond standard modes of data interpretation in experiments, with the goal of tying inferences directly to the Earth system models that provide our best understanding of possible future climate scenarios. In this way, our proposed research contributes to accomplishing the long-term measure of the Department of Energy’s BER. Objectives of the Project This project will examine the sensitivity of carbon in land ecosystems to environmental change, focusing on carbon contained in soil, and the role of carbon-nitrogen interactions in regulating ecosystem carbon storage. The project will use a combination of empirical measurements, mathematical models, and statistics to partition effects of climate change on soil into processes enhancing soil carbon and processes through which it decomposes. By synthesizing results from experiments around the world, the proposed approach will provide novel insight on ecological controls and responses across broad spatial and temporal scales. In this way, a second objective of the project is to develop new approaches in meta-analysis using principles of element mass balance and large datasets to derive metrics of ecosystem responses to environmental change. The project will use meta-analysis to test how nutrients regulate responses of ecosystems to elevated CO2 and warming, focusing on processes that regulate longterm C balance. Finally, the project will create a platform for data distribution in climate change research, designed specifically to facilitate future syntheses of results relevant to Earth system models.