On strategies for reducing greenhouse gas emissions

Equity is of fundamental concern in the quest for international cooperation to stabilize greenhouse gas concentrations by the reduction of emissions. By modeling the carbon cycle, we estimate the global CO(2) emissions that would be required to stabilize the atmospheric concentration of CO(2) at levels ranging from 450 to 1,000 ppm. These are compared, on both an absolute and a per-capita basis, to scenarios for emissions from the developed and developing worlds generated by socio-economic models under the assumption that actions to mitigate greenhouse gas emissions are not taken. Need and equity have provided strong arguments for developing countries to request that the developed world takes the lead in controlling its emissions, while permitting the developing countries in the meantime to use primarily fossil fuels for their development. Even with major and early control of CO(2) emissions by the developed world, limiting concentration to 450 ppm implies that the developing world also would need to control its emissions within decades, given that we expect developing world emissions would otherwise double over this time. Scenarios leading to CO(2) concentrations of 550 ppm exhibit a reduction of the developed world's per-capita emission by about 50% over the next 50 years. Even for the higher stabilization levels considered, the developing world would not be able to use fossil fuels for their development in the manner that the developed world has used them

Global perspective

International audienc

Emissions and Atmospheric CO 2 Stabilization: Long-Term Limits and Paths

carbon cycle, CO 2 , emissions, scenario, stabilization,

Convective heat transfer in a rotating square channel with oblique cross section

A numerical study has been performed to study the fluid flow and convective heat transfer inside a rotating square isothermal channel with the channel cross-section having oblique angles to the rotational axis. The channel is subjected to a radial rotation. Computations are carried out for flows at Re =500, 1000 and 2000 and range from the channel entrance to a flow distance of 300 and 600 times the hydraulic diameter, depending upon the Reynolds number. Results reveal the vortex flow structures, and consequently the heat transfer phenomena, are quite different from that of previous studies with zero oblique angle. The channel with 45 degree oblique angle yields the best overall heat transfer performance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47815/1/466_2004_Article_BF00377603.pd