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. Author manuscript; available in PMC: 2020 Mar 1.
Published in final edited form as: Nat Clim Chang. 2019 Sep;9:719–725. doi: 10.1038/s41558-019-0553-2

Figure 2. Fractional Area of Emergence for Anthropogenic Trends in Ocean Biogeochemical and Physical variables.

Figure 2.

A time series of the percent of the global ocean area with locally-emergent anthropogenic trends illustrates the disparity of emergence timescales for anthropogenic changes in the ocean carbon cycle. Emergence is defined as the point in time when the LE’s signal-to-noise ratio for a linear trend referenced to year 1990 first exceeds a magnitude of 2, representing 95% confidence of the identification of an anthropogenic trend in the LE. Omega applies to the saturation of both aragonite and calcite forms of calcium carbonate, for which emergence times are approximately equivalent. The CaCO3 and soft-tissue pump are calculated as the export flux at 100 meters (m) depth of CaCO3 and particulate organic carbon, respectively. The heat content is calculated as an integral over 0–700 meters, whereas the O2 inventories consider the integral 200–600m, and chlorophyll inventories are considered over 0–500m. NPP represents an integral over 0–100m. All other variables represent sea surface properties.