Evaluating CO2 reduction strategies in the US

We constructed a model to simulate emissions of CO2 from electricity generation in the US and, using the model, we developed 20-year projections of emissions under various regulatory scenarios. We concluded that the State renewable portfolio standards (RPS) adopted by 23 States will decrease emissions by a mere 4.5% relative to business-as-usual (BaU) conditions. By comparison, possible national GHG control strategies such as applying the California standards to the entire US or imposing a 2000-level cap on CO2 emissions would result in a reduction of 34% relative to BaU. Finally, imposing a 1990-level cap on CO2 emissions would result in a reduction of 49% relative to BaU. Notwithstanding these findings, we demonstrate that, even the most ambitious GHC reduction strategies being contemplated in the US for the energy generating sector will not reach the 60% reduction, generally regarded as necessary. on a global scale and from all CO2-emitting sectors to prevent an atmospheric warming of about 2 degrees. We conclude that efforts now need to focus, not only on reducing GHG emissions, but equally on preparing for the inevitable climate change. Beyond the scenarios evaluated in this research, the model can serve as a flexible tool for determining whether a given strategy will achieve the desired CO2 emission reduction goal. (C) 2009 Elsevier B.V. All rights reserved.