Possible reading topics:
0. History of global warming
Arrhenius, 1896: [pdf]

1. Uncertainties in land-use estimate and implication for the missing carbon sink:
DeFries
Houghton
... and other refs in the Houghton chapter

2. Atmopsheric inversion of CO2 sources and sinks (focus on the mean over a period of time and global scale); Northern Hemisphere sink
P. P. Tans, I. Y. Fung, T. Takahashi, Science 247, 1431 (1990).
K. R. Gurney et al., Nature 415, 626 (2002).
Roedenbeck, C., S. Houweling, M. Gloor, and M. Heimann (2003), CO2 flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport, Atmos. Chem. Phys., 3, 1919–1964.

Joint ocean-atmosphere inversion  (New)
Jacobson et al.  2006

3. What caused glacial-interglacial CO2 change?
Reviews:         Broecker and Peng 1998
                        Archer et al., 2000
Newer ideas:    Zeng 2003, 2007
                        Toggweiler et al. 2005
                         Paillard and Perinin 2005

4. Combination of mechanisms responsible for the missing carbon sink using bottom-up approach
Review:  Sarmiento, J.L. and N. Gruber. Sinks for anthropogenic carbon, Physics Today, 55(8), 30-36, 2002.
J. P. Caspersen et al., Science 290, 1148 (2000).
W. H. Schlesinger, J. Lichter, Nature 411, 466 (2001).
S. W. Pacala et al., Science 292, 2316 (2001).
G. C. Hurtt et al., Proc. Natl. Acad. Sci. USA 99, 1389 (2002).
Other refs from Sarmiento and Gruber

5. How did we figure out the anthropogenic ocean carbon sink?

6. Novel techniques useful for distinguishing land vs. ocean sink
    O2/N2   (Keeling et al.)
    C13

6. Sources and their current and future changes of CO2 emission, energy:
Raupach MR
Dynamics of resource production and utilisation in two-component biosphere-human and terrestrial carbon systems
HYDROLOGY AND EARTH SYSTEM SCIENCES 11 (2): 875-889 2007

Raupach MR, Marland G, Ciais P, et al.
Global and regional drivers of accelerating CO2 emissions
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA104 (24): 10288-10293 JUN 12 2007


References:

The 'missing' carbon sink:

Reviews:
Sarmiento, J.L. and N. Gruber. Sinks for anthropogenic carbon,Physics Today, 55(8), 30-36, 2002.
Houghton, R., 2003: chapter in Biogeochemistry, Schlesinger (Ed.).

Field, C., 2003

Bottom-up
J. P. Caspersen et al., Science 290, 1148 (2000).
W. H. Schlesinger, J. Lichter, Nature 411, 466 (2001).
S. W. Pacala et al., Science 292, 2316 (2001).
G. C. Hurtt et al., Proc. Natl. Acad. Sci. USA 99, 1389 (2002).

Inferred from atmospheric CO2 measurements (top-down approach)
P. P. Tans, I. Y. Fung, T. Takahashi, Science 247, 1431 (1990).
K. R. Gurney et al., Nature 415, 626 (2002).
Roedenbeck, C., S. Houweling, M. Gloor, and M. Heimann (2003), CO2 flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport, Atmos. Chem. Phys., 3, 1919–1964.

Joint ocean-atmosphere inversion
Jacobson et al.

Uncertainty in land use
DeFries
Houghton
... and other ref in the Houghton chapter


Interannual variability

Atmosphere
Bacastow, R. B. (1976), Modulation of atmospheric carbon dioxide by the Southern Oscillation, Nature, 261, 116–118.
Keeling, C. D., T. P. Whorf, M. Wahlen, and J. Vanderplicht (1995), Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980, Nature, 375, 666–670.
Roedenbeck, C., S. Houweling, M. Gloor, and M. Heimann (2003), CO2 flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport, Atmos. Chem. Phys., 3, 1919–1964.
Peylin, P., P. Bousquet, C. Le Quéré, S. A. Sitch, P. Friedlingstein, G. McKinley, N. Gruber, P. Rayner, and P. Ciais (2005), Multiple constraints on regional CO2 flux variations over land and oceans, Global Biogeochem. Cycles, GB1011, doi:10.1029/2003GB002214

Land
Zeng, N., A. Mariotti, and P. Wetzel (2005), Terrestrial mechanisms of interannual CO2 variability, Global Biogeochem. Cycles, 19, GB1016, doi:10.1029/2004GB002273.
McGuire, A. D., et al. (2001), Carbon balance of the terrestrial biosphere in the twentieth century: Analyses of CO2, climate, and land use effects with four process-based ecosystem models, Global Biogeochem. Cycles, 15(1), 183–206

Ocean
Le Quéré, C., et al. (2003), Two decades of ocean CO2 sink and variability, Tellus, B55(2), 649–656.
Wetzel, P., A. Winguth, and E. Maier-Reimer (2005), Sea-to-air CO2 flux from 1948 to 2003: A model study, Global Biogeochem. Cycles, 19, GB2005, doi:10.1029/2004GB002339.

Fire
van der Werf, G. R., et al.
(2004), Continental-scale partitioning of fire emissions during the 1997 to 2001 El Niño/La Niña period, Science, 303, 73–76.  Abstract »    Full Text »    PDF »
Page, S. E., et al. (2002), The amount of carbon released from peat and forest fires in Indonesia during 1997, Nature, 420, 61–65.

Drought
Drier summers cancel out the CO2 uptake enhancement induced by warmer springs.
A. Angert, S. Biraud, C. Bonfils, C. C. Henning, W. Buermann, J. Pinzon, C. J. Tucker, and I. Fung (2005).
PNAS 102: 10823-10827    Abstract »    Full Text »    PDF »
Zeng N., H. Qian, C. Roedenbeck, M. Heimann (2005), Impact of 1998–2002 midlatitude drought and warming on terrestrial ecosystem and the global carbon cycle, Geophys. Res. Lett., 32, L22709, doi:10.1029/2005GL024607. [Abstract+Article]
Ciais 2005: European heatwave in 2003.

Carbon Climate feedback
Evolution of carbon sinks in a changing climate.
I. Y. Fung, S. C. Doney, K. Lindsay, and J. John (2005).
PNAS 102: 11201-11206    Abstract »    Full Text »    PDF »
Greening of the North:  carbon source or sink?
Lucht, W., I. C. Prentice, R. B. Myneni, S. Sitch, P. Friedlingstein, W. Cramer, P. Bousquet, W. Buermann, and B. Smith (2002), Climatic control of the high-latitude vegetation greening trend and Pinatubo effect, Science, 296, 1687–1689.[CrossRef]