Figure 5.10

Figure caption

Figure 5.10 | Trends of the net land CO₂ sink and related vegetation observations during 1980–2019. (a) Net land CO₂ sink. The residual net land CO₂ sink is estimated from the global CO₂ mass balance (fossil fuel emissions minus atmospheric CO₂ growth rate and ocean CO₂ sink). Inversions indicate the net land CO₂ sink estimated by an ensemble of four atmospheric inversions. Dynamic Global Vegetation Models (DGVMs) indicate the mean net land CO₂ sink estimated by 17 dynamic global vegetation models driven by climate change, rising atmospheric CO₂, land-use change and nitrogen deposition change (for carbon-nitrogen models). The positive values indicate net CO₂ uptake from the atmosphere. (b) Normalized difference vegetation index (NDVI). The anomaly of global area-weighted NDVI observed by Advanced Very High Resolution Radiometer (AVHRR) and MODIS satellite sensors. AVHRR data are accessible during 1982–2016 and MODIS data are accessible during 2000–2018. (c) Near-infrared reflectance of vegetation (NIRv) and contiguous solar-induced chlorophyll fluorescence (CSIF). The standardized anomaly of area-weighted NIRv during 2001–2018 (Badgley et al., 2017) and CSIF during 2000–2018 (Zhang et al., 2018). (d) Gross primary production (GPP). The GPP from Cheng et al. (2017), DGVMs and MODIS GPP product (MOD17A3). GPP from Cheng et al. (2017) is based on an analytical model driven by climate change, rising atmospheric CO₂, AVHRR leaf area index datasets and evapotranspiration datasets. GPP from DGVMs is the ensemble mean global GPP estimated by the same 17 DGVMs that provide the net land CO₂ sink estimates. Shaded area indicates 1–σ inter-model spread except for atmospheric inversions, whose ranges were used due to limited number of models. Further details on data sources and processing are available in the chapter data table (Table 5.SM.6).