Fig. 2.

Trends in net CO₂ flux and its components for the past 30 years. Results of two trend tests (Mann–Kendall and Theil slope tests) on a, net CO₂ flux (NBP) from the TRENDY S3 (seven models: blue circles for 1980–1999 and red circles for 1990–2009, and ensemble average: a cyan upper triangle for 1980–1999 and an orange upper triangle for 1990–2009) are shown along with those on the atmospheric CO₂ inversions (ensemble average: a cyan lower triangle for 1980−1999 and an orange lower triangle for 1990–2009) and Δbiomass (a green square for 1994−2009). The trend tests on attributing factors to NBP are illustrated for b, the LUC effect and c, CO₂ fertilization+climate effects. Size of markers indicates statistical significance of trends: larger (p < 0.05) and smaller (p ≥ 0.05)