- Student Dissertation or Thesis
In response to the threat of global warming a variety of policy measures have been proposed to reduce the emissions of carbon dioxide (CO2). However, policies which reduce CO2 emissions will also decrease the emissions of greenhouse-relevant gases methane, nitrous oxide, nitrogen oxides, carbon monoxide, and sulfur oxides. When these additional effects are overlooked the net effect of CO2 reduction policies on global warming is understated. Thus, emissions of all greenhouse-relevant gases should be included when evaluating CO2 reduction policies.
Other proposals which recognize the need to reduce emissions of all greenhouse gases have called for the reduction of a “CO2-equivalent" amount. Policymakers evaluate these policies by using a Global Warming Potential (GWP) which is an index that supposedly indicates the relative radiative power of a greenhouse gas with respect to CO2 . This method, however, is flawed, as calculation of the GWP depends critically on the lifetime of the gas as well as the radiative effect of CO2 which can change depending on the composition of the atmosphere. When analyzing the effect of gases on global warming, an atmospheric chemistry model which describes the interactions of all the gases should be used in place of the GWP. In this case, specification of future emissions of all greenhouse-relevant gases is also required. This thesis addresses these two problems by developing a model which forecasts emissions of all greenhouse-relevant gases. This emissions model uses the GREEN model as the underlying economic model and incorporates the emissions of greenhouse-relevant gases from activities in energy, agriculture, industry, and land use. The results of the model are then fed into an atmospheric chemistry model to evaluate the effect on warming.
The atmospheric chemistry model is used to compare the results of a reference case with a Toronto-type agreement. The thesis finds that including other greenhouse-relevant gases results in an additional decrease of 40% in warming as compared to when only CO2 is specified. Additional analyses are performed to illustrate the interaction between chemical species and the importance of including all greenhouse-relevant gases when evaluating global warming policies.