Fig. 4. Radiative forcing induced by direct and indirect human activities on grasslands worldwide a in the year 2012 and b for the period 1900–2012.
The ‘Total’ column/line is the total contribution of grassland to the global radiative forcing (RF), accounting for the land-use change induced albedo change related to grassland, land-use change emission related to grassland (CO2 ELUC) and the three grassland greenhouse gas (GHG) fluxes (CO2 soil sink, CH4 and N2O). In a, the RF of each component is further divided for managed and sparsely grazed grasslands, and is shown as an empty bar outlined in the same colour with (managed grasslands) and without (sparsely grazed grasslands) hatching, respectively. The stacked bar for CO2 ELUC includes, from bottom to top, the effect from deforestation to pasture and conversion of grassland to cropland. The stacked bar for CH4 includes, from bottom to top, the direct effect from CH4, and its associated effects through tropospheric O3 and lifetime change induced by ozone precursors, and stratospheric H2O. The stacked bar for N2O includes, from bottom to top, the direct effect from N2O, and its associated effects through stratospheric O3. The uncertainties shown in a are 1-sigma standard deviation. The coloured shaded areas in b are the 1-sigma confidence interval derived from our uncertainty assessment (see ‘Methods').