Reducing the risk of global warming from CFC alternatives: A scientific basis for policy options
The thesis develops a methodology for accurately estimating the global warming potential of several proposed CFC substitutes such as HFCs and HCFCs for policy making.
The first part of the methodology is based on ab initio quantum mechanical calculations at the Hartree-Fock (HF) and second order perturbation theory (MP2) using a variety of basis sets for estimating the geometries, dipole moments, fundamental frequencies and infrared absorptions of: CH$\sb3$F (HFC-41), CH$\sb2$F$\sb2$ (HFC-32), CHF$\sb3$ (HFC-23), CF$\sb4$ (HFC-14), CHClF$\sb2$ (HCFC-22), CH$\sb3$CH$\sb2$F (HFC-161), CH$\sb3$CF$\sb2$H (HFC-152a), CH$\sb2$FCH$\sb2$F (HFC-152), CH$\sb3$CF$\sb3$ (HFC-143a), CH$\sb2$FCHF$\sb2$ (HFC-143), CH$\sb2$FCF$\sb3$ (HFC-134a), CHF$\sb2$CHF$\sb2$ (HFC-134), CHF$\sb2$CF$\sb3$ (HFC-125), CF$\sb3$CF$\sb3$ (HFC-116), CH$\sb3$CFCl$\sb2$ (HCFC-141b), CH$\sb3$CF$\sb2$Cl (HCFC-142b), CHCl$\sb2$CF$\sb3$ (HCFC-123), CHClFCF$\sb3$ (HCFC-124) and their most stable atmospheric breakdown products: C(O)HF, C(O)F$\sb2$, C(O)FCl, CF$\sb3$C(O)F, CF$\sb3$C(O)Cl, CF$\sb3$C(O)OH. Our values are compared to the literature ones.
In the second part of the methodology we estimate the instantaneous infrared radiative forcings for each one of these molecules based on a simplistic approach and on computer climate model calculations, using our infrared band intensities. A 2-D global climate model was used for obtaining their global warming potentials.
In the third part we assess the total amount of CO$\sb2$ emitted during the lifetime of CFC-11, CFC-12, and their replacements HCFC-123 and HFC-134a based on an industrial ecology model. We include the amount of CO$\sb2$ emitted during the synthesis of the chemicals in a manufacturing plant, that emitted during their recycling as well as the equivalent CO$\sb2$ emissions of their atmospheric breakdown products. For the refrigeration sector, we also considered the impact of different fuel scenarios and the production of electricity considering the specific fuel mix of different countries.
Based on these findings in the last part of the thesis we provide policy recommendations for developing countries in choosing among different CFC alternative options and conclude by recommending adoption of not-in-kind technology.
0768: Environmental science
0616: International law
0616: International relations