Atmospheric carbon dioxide (CO₂) levels have doubled since the last Ice Age (from 175 ppm) and increased 25 to 30% during the last 150 years (from 275 to 355 ppm). CO₂ levels are expected to double again over the next century.

Carbon dioxide and soil moisture flux measurements are being made at the Walnut Gulch Experimental Watershed.

The role of grasslands in mitigating human impacts on the global carbon balance and moisture fluxes is being evaluated to determine how carbon source/sink relationships and moisture fluxes change along large-scale natural environmental gradients.