Increased soil emissions of potent greenhouse gases under increased atmospheric CO2

Abstract

Increasing concentrations of atmospheric carbon dioxide (CO2) can affect biotic and abiotic conditions in soil, such as microbial activity and water content1, 2. In turn, these changes might be expected to alter the production and consumption of the important greenhouse gases nitrous oxide (N2O) and methane (CH4) (refs 2, 3). However, studies on fluxes of N2O and CH4 from soil under increased atmospheric CO2 have not been quantitatively synthesized. Here we show, using meta-analysis, that increased CO2 (ranging from 463 to 780 parts per million by volume) stimulates both N2O emissions from upland soils and CH4 emissions from rice paddies and natural wetlands. Because enhanced greenhouse-gas emissions add to the radiative forcing of terrestrial ecosystems, these emissions are expected to negate at least 16.6 per cent of the climate change mitigation potential previously predicted from an increase in the terrestrial carbon sink under increased atmospheric CO2 concentrations4. Our results therefore suggest that the capacity of land ecosystems to slow climate warming has been overestimated.

Increased Methane Emissions by an Introduced Phragmites australis Lineage under Global Change

“…In conclusion, our data support the hypothesis that increased plant productivity will increase CH 4 emissions from wetlands (van Groenigen et al 2011). Productivity increased as the result of genotypic variability within a single species, and as the result of increased resource availability (i.e.…”

“…Previous studies have reported that elevated CO 2 alone can increase wetland CH 4 emissions (reviewed in van Groenigen et al 2011). In the present experiment, elevated CO 2 stimulated CH 4 emissions only in combination with added N, providing an example of an interaction among global change factors that must be considered in order to forecast changes in emissions of this greenhouse gas.…”

“…Elevated CO 2 generally stimulates CH 4 emissions in both natural ecosystems and agricultural systems (Xu et al 2004;Lou et al 2008;van Groenigen et al 2011). However, different plant species vary in their growth response to elevated CO 2 (Poorter and Navas 2003), and in their sensitivity to elevated CO 2 stimulation of CH 4 emissions (Vann and Megonigal 2003), making it difficult to predict the effects of elevated CO 2 on radiative forcing when it is accompanied by a change in dominant plant species.…”

Environmental applications using graphene composites: water remediation and gas adsorption

“…139 What the outcomes of this increase in greenhouse gases will be is the unanswered question. 140,141 Regardless, action should be taken and this requires the adsorption of these gases. Graphene, like other carbon-based materials, is light and cheap to produce in comparison to other solid state gas adsorbent materials.…”

Rice, fish, and the planet

“…However, this finding underestimates the contribution of methane to the climate problem, because its interaction with aerosols increases its activity; also, its relatively short residence time in the atmosphere makes it especially sensitive to corrective intervention (8). There is also a synergistic effect, because increased amounts of atmospheric CO 2 are predicted to stimulate methane emissions from rice paddies (9). Because the soil methanogens quickly become dormant when the paddies are drained, emissions can be reduced by decreasing the amount of time that the paddies are submerged.…”