Global Carbon Mitigation Research Articles

The national security dividend of global carbon mitigation

Energy and environmental security objectives are often conflated in political circles and in the popular press. Results from a well-established integrated assessment model suggest that policies designed to stabilize atmospheric carbon dioxide concentrations at levels above ∼500 ppm generally do not align with policies to curb global oil dependence, because these atmospheric objectives can be achieved largely through reductions in global coal consumption. Policies designed to stabilize atmospheric carbon dioxide at levels below ∼500 ppm, on the other hand, directly facilitate the alignment of environmental and security objectives because atmospheric targets in this range demand significant reductions in both coal and oil use. Greater recognition that investment in carbon mitigation can yield significant security dividends may alter the political cost–benefit calculus of energy-importing nations and could increase the willingness of some key global actors to seek binding cooperative targets under any post-Kyoto climate treaty regime.

Potential for carbon sequestration in European soils: preliminary estimates for five scenarios using results from long‐term experiments

One of the main options for carbon mitigation identified by the IPCC is the sequestration of carbon in soils. In this paper we use statistical relationships derived from European long‐term experiments to explore the potential for carbon sequestration in soils in the European Union. We examine five scenarios, namely (a) the amendment of arable soils with animal manure, (b) the amendment of arable soils with sewage sludge, (c) the incorporation of cereal straw into the soils in which it was grown, (d) the afforestation of surplus arable land through natural woodland regeneration, and (e) extensification of agriculture through ley‐arable farming. Our calculations suggest only limited potential to increase soil carbon stocks over the next century by addition of animal manure, sewage sludge or straw ( 15 Tg C y–1), but greater potential through extensification of agriculture (≈ 40 Tg C y–1) or through the afforestation of surplus arable land (≈ 50 Tg C y–1). We estimate that extensification could increase the total soil carbon stock of the European Union by 17%. Afforestation of 30% of present arable land would increase soil carbon stocks by about 8% over a century and would substitute up to 30 Tg C y–1 of fossil fuel carbon if the wood were used as biofuel. However, even the afforestation scenario, with the greatest potential for carbon mitigation, can sequester only 0.8% of annual global anthropogenic CO2‐carbon. Our figures suggest that, although efforts in temperate agriculture can contribute to global carbon mitigation, the potential is small compared to that available through reducing anthropogenic CO2 emissions by halting tropical and sub‐tropical deforestation or by reducing fossil fuel burning.