Ballantyne et al. (2012)
Also: Ballantyne et al. 2012
Increase in observed net carbon dioxide uptake by land and oceans during the last 50 years
Ballantyne, A. P., C. B. Alden, J. B. Miller, P. P. Tans, and J. W. C. White, 2012: Increase in observed net carbon dioxide uptake by land and oceans during the last 50 years. Nature, 488, 70-72. Link to paper
doi:10.1038/nature11299
References
All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.