Table 1 Modelled source contributions to global river CO2 emissions

From: Old carbon routed from land to the atmosphere by global river systems

 

Vertical CO2 emissions

Monte Carlo simulation

Bayesian isotope mixing model

Proportion

CO2 emissions (Pg C year−1)

Proportion

CO2 emissions (Pg C year−1)

Decadal

0.41 ± 0.16

0.9 ± 0.3

0.50 ± 0.12

1.0 ± 0.2

Millennial

0.52 ± 0.16

1.1 ± 0.3

0.34 ± 0.17

0.7 ± 0.3

Petrogenic

0.07 ± 0.01

0.1 ± 0.0

0.15 ± 0.06

0.3 ± 0.1

‘Old’ carbon

0.59 ± 0.17

1.2 ± 0.3

0.49 ± 0.23

1.0 ± 0.4

  1. First-order estimates of the contributions of decadal, millennial and petrogenic carbon sources to CO2 emissions (proportions and flux, Pg C year−1; mean ± 1σ) by global river systems from the two-endmember isotope mixing model and Monte Carlo simulation (assuming known petrogenic inputs as a prior; equation (7); Extended Data Fig. 5) and the three-endmember Bayesian isotope mixing model (excluding any previous fluxes, mean ± 1σ from the model scenarios; Supplementary Table 2 and Extended Data Fig. 6). ‘Old’ carbon represents combined millennial and petrogenic contributions.
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