Evidence for accelerated climate-driven weathering and sulfate export in high alpine environments

High elevation alpine ecosystems—the "water towers of the world"—are warming at rates that far exceed those of lower elevations. Active geomorphic features, such as glaciers and permafrost, leave alpine ecosystems susceptible to climate-induced alteration. We examined recent changes in high-elevation stream chemistry in an alpine catchment of Colorado, USA and found strong evidence of increasing sulfate and base cation fluxes. To better understand these recent changes and to examine the potential causes of increased sulfur and base cation fluxes in surface waters, we present a high resolution 33-year record of atmospheric deposition (NADP site: CO02) to evaluate what factors may be driving this shift in stream chemistry. Our mass balance analysis and additional sulfur isotopic data suggests that recent warming is stimulating changes to hydrology and/or geomorphic processes, which in turn lead to accelerated weathering of bedrock. There is no evidence to suggest that atmospheric deposition is responsible for elevated stream export. This trend is also represented globally including in the Rocky Mountains of the United States, western Canada, the European Alps, the Icelandic Shield, and the Himalayas in Asia. All of these locations have experienced rapid increases in temperature during recent years, suggesting a climate-controlled change in sulfur and base cation export from mountainous regions via mineral weathering.