<p><strong>Abstract.</strong> Becker et al. (2013) argue that an afforestation of 0.73 × 10⁹ ha with <i>Jatropha curcas</i> plants would generate an additional terrestrial carbon sink of 4.3 PgC yr⁻¹, enough to stabilise the atmospheric mixing ratio of carbon dioxide (CO₂) at current levels. However, this is not consistent with the dynamics of the global carbon cycle. Using a well-established global carbon cycle model, the effect of adding such a hypothetical

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... k leads to a reduction of atmospheric CO₂ levels in the year 2030 by 25 ppm compared to a reference scenario. However, the stabilisation of the atmospheric CO₂ concentration requires a much larger additional sink or corresponding reduction of anthropogenic emissions.</p>