Chemical transport modeling of potential atmospheric CO2 sinks

Abstract

The potential for carbon dioxide (CO 2 ) sequestration via engineered chemical sinks is investigated using a three dimensional chemical transport model (CTM). Meteorological and chemical constraints for flat or vertical systems that would absorb CO 2 from the atmosphere, as well as an example chemical system of calcium hydroxide (Ca(OH) 2 ) proposed by Elliott et al. [Compensation of atmospheric CO 2 buildup through engineered chemical sinkage, Geophys. Res. Lett. 28 (2001) 1235] are reviewed. The CTM examines land based deposition sinks, with 4°Â 5°latitude/longitude resolution at various locations, and deposition velocities (v). A maximum uptake of $20 Gton (10 15 g) C yr À1 is attainable with v > 5 cm s À1 at a mid-latitude site. The atmospheric increase of CO 2 (3 Gton yr À1 ) can be balanced by an engineered sink with an area of no more than 75,000 km 2 at v of 1 cm s À1 . By building the sink upwards or splitting this area into narrow elements can reduce the active area by more than an order of magnitude as discussed in Dubey et al. [31].

Carbon neutral hydrocarbons

“…Air capture, as opposed to biomass growth, is not limited by land area rather by the rate of CO 2 diffusion to the boundary layer, analogous to the physics that limits wind turbine spacing (Keith et al 2006). Previous work has shown that air-capture rates are at least one order of magnitude larger than biomass growth (Johnston et al 2003). This value reflects the large-scale limitations of CO 2 transport in the atmospheric boundary layer.…”

Electrical Energy Storage with Engineered Biological Systems

“…However, photosynthesis is far from perfect. Photosynthesis draws carbon from the atmosphere at an annually averaged rate of only 1 to 2 × 10 18 molecules of CO2 m -2 s -1 [34], between 25 and 70 times less than the maximum possible uptake rate of carbon from the atmosphere of 5 to 7 × 10 19 molecules of CO2 [34,35]. As a result, the globally and annually averaged efficiency of photosynthesis ranges from between 0.25% [35] to 1% [36], with the best overall efficiencies seen in the field of between 2.4% for C3 plants [37], 3.4% for C4 plants [38] and 3% for algae grown in bubbled photobioreactors [39].…”

Assessment of the impact of salinity and irradiance on the combined carbon dioxide sequestration and carotenoids production by Dunaliella salina: A mathematical model

“…The average concentration of anthropogenic CO 2 in the atmosphere has increased from 278 ppmv in the pre-industrial era to 358 ppmv in 1996 (Simeonova and Diaz-Bone, 2005). Simulation of carbon cycle predict that if CO 2 emissions are maintained at the present levels, by 2,100 CO 2 atmospheric concentration will reach 500 ppmv (Johnston et al, 2003).…”

“…To restrain this expansion, Kyoto Protocol established the goal of reducing GHG emissions in 5.2% during the period from 2008 to 2012, based on 1990 data (Simeonova and Diaz-Bone, 2005). Given the fossil fuels burning is the major contributor to anthropogenic CO 2 ($6 Gt C/year) (Johnston et al, 2003), a reduction of the level of burned fossil fuels would contribute to limiting atmospheric CO 2 . However, it was predicted that, until year 2020, energy demand will still be supplied by fossil fuels (Ametistova et al, 2002).…”

“…The ''natural'' sequestration of CO 2 by plants and also by its dissolution in the oceans account for 50% of the emissions, while the remaining CO 2 accumulates in the atmosphere (Ametistova et al, 2002;Johnston et al, 2003). CO 2 sequestration by algae, to mitigate GHG, shows promising perspectives due to their photosynthetic capacity and growth rates larger than those observed for higher plants.…”