The upwelling of nutrients from the deep ocean sets the flow rate of carbon moved by the biological pump by bringing nutrients to the photic zone. Here solar energy converts inorganic carbon to organic material that cannot communicate with the atmosphere. As a consequence of gravitational sinking, the majority of the carbon in the biological cycle is in the deep ocean isolated from the atmosphere and can be considered part of a closed cycle. Increasing the carbon flow of the biological pump, that is increasing the pumps capacity from its present value of 4.5GtC/yr, will have the effect of drawing carbon from atmosphere and the land to augment the cycle.

By coupling an ecosystem model to a Pacific Ocean setup of ROMS (the Regional Oceanic Modeling System) at eddy-permitting resolution and performing experiments in scale ranging from the patch size of in situ experiments to the several 100km size of coarse resolution models, we aim to establish a connection between large-scale global model studies and the many insights emerging from the very small-scale patch fertilization studies. Our research will be guided by three hypotheses, which state that the export efficiency of fertilization, i.e. the amount of carbon that is being exported from the surface ocean per unit of iron applied to the ocean, will depend critically on the size and duration of the experiment.

Prognostic simulation of carbon sequestration and carbon management must provide for the influence of potential changes in future atmospheric CO₂ concentrations and climate on carbon cycle processes. The conventional approach is to use various scenarios of changes in atmospheric CO₂ and climate as external inputs to carbon cycle models. However, this approach decouples potentially important feedbacks between the carbon cycle and climate, and thus contributes uncertainty to the simulation of future carbon sequestration and the evaluation of carbon management options. Here we describe modeling results that analyze components of this uncertainty. We describe how coupling a carbon management model with a climate model in fully coupled climate-carbon simulations influences the analysis and interpretation of terrestrial ecosystem sequestration as an option for future carbon management.

Air samples are collected through the Climate Monitoring and Diagnostics Laboratory (CMDL) global network, including a cooperative program for the carbon gases which provides samples from about 100 global clean air sites, including measurements at 5 degree latitude intervals from three ship routes. Greenhouse gas concentrations are analyzed in terms of the changes in radiative forcing during the 26-year period encompassing 1979 through 2004. The growing fraction of the total radiative forcing due to carbon dioxide is emphasized and the nature of the interannual variations in the radiative forcing is explored. The interannual change in total radiative forcing is used to define an Annual Greenhouse Gas Index (AGGI).

An ocean general circulation model (OGCM) is used to simulate the direct injection of CO₂ near Tokyo. Our results confirm that direct injection can sequester large amounts of CO₂ from the atmosphere when disposal is made at sufficient depth but show that the calculated efficiency is sensitive to the choice of physical model. Moreover, we show, in an OGCM and under a reasonable set of economic assumptions, that sequestration effectiveness is quite high for even shallow injections. However, the severe acidification that accompanies injection and the impossibility of effectively monitoring injected plumes argue against the large-scale viability of this technology. Our coarse-grid models show that injection at the rate of 0.1 Pg-C/yr lowers pH near the site of injection by as much as 0.7-1.0 pH-unit. We also show that, after several hundred years, one would effectively need to survey the entire ocean in order to accurately verify the inventory of injected carbon. These results suggest that while retention may be sufficient to justify disposal costs, other practical problems will limit or at best delay widespread deployment of this technology.

Carbon management (CM) domain in Russia is defined by carbon (C) sequestration potentials in vegetation and soil and options for C flux manipulations in line with regional indicators of the carbon cycle (CC).

A field experiment on the Swiss Plateau was designed to measure the greenhouse gas (GHG) budget of two parallel fields after conversion from arable crop rotation to cut grassland and managed either intensively or extensively. Measurements of N₂O fluxes with chambers and of CO₂ with eddy flux towers were complemented by estimates of C-imports (organic fertilizers) and C-exports (yield). The results indicate that newly established grassland plots act as a net GHG sink when management intensity (fertilization and cutting) is high, while conversion to extensive grasslands leads to an initial net loss of GHG.

If liquid CO₂ is stored as a dense "lake" on the deep ocean floor, it is expected to dissolve in seawater. Ocean currents and turbulence may increase the net rate of CO₂ release by several orders of magnitude compared to molecular diffusion. However, density stratification in the seawater created by dissolved CO₂ will tend to reduce vertical mixing. By comparing results from different model formulations, this study aims to increase our understanding of the processes in such a layer of CO₂-enriched seawater, and decrease the uncertainties about storage efficiency and subsequent environmental impact. The study is also relevant to the case of saturated water leaking from subseabed geological storage through bottom sediments.

In this paper, we use a coupled climate and carbon cycle model to investigate the global climate and carbon cycle changes out to year 2300 that would occur if CO₂ emissions from all the currently estimated fossil fuel resources were released to the atmosphere. By year 2300, the global climate warms by about 8 K and atmospheric CO₂ reaches 1423 ppmv. In our simulation, the prescribed cumulative emission since pre-industrial period is about 5400 Gt-C by the end of 23^rd century. At year 2300, nearly 45% of cumulative emissions remain in the atmosphere. In our simulations both soils and living biomass are net carbon sinks throughout the simulation. Despite having relatively low climate sensitivity and strong carbon uptake by the land biosphere, our model projections suggest severe long-term consequences for global climate if all the fossil-fuel carbon is ultimately released to the atmosphere.