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The primary objectives of recent energy initiatives have been: (1) lowering greenhouse gas (GHG) emissions; and (2) increasing US energy security by reducing oil imports for the purposes of making the US less vulnerable to the actions of other countries. The concern is that relying on sometimes adversarial, sometimes unstable countries for a quarter of our oil carries certain risks. For that reason, reducing the external oil dependence has been of interest to policy makers. This paper examines the impacts and costs of transportation-based policies on light-duty vehicle fleet energy usage and emissions. Using the 2010 elastic version of the US Environmental Protection Agency's Market Allocation (MARKAL) model, recent increases in US Corporate Average Fuel Economy (CAFE) Standards are compared to what some economists suggest would be a much more “efficient” alternative-asystem-wide oil tax internalizing a number of environmental externalities. We discover that our series of oil taxes produce larger and more cost-effective reductions in economy-wide emissions than CAFE. The same cannot be said in regards to net oil imports. Stricter fuel economy regulations result in much larger cutbacks in imports than the oil tax. In fact, we found that in 2040 import demands are roughly 250 million BOE (barrels of oil equivalent) higher with our oil tax regime than they are with CAFE. The additional import reductions achieved with stricter CAFE Standards do come, however, at a much larger cost to society. A great deal of these additional economic costs stems from greater usage of more energy-efficient automobiles and the higher initial capital costs associated with their adoption. In our supplementary analysis, we find that even if the costs of these types of vehicles are lowered by as much as 75%, oil taxes would still be able to maintain their competitive edge over CAFE standards in regards to cost-effectiveness. [ABSTRACT FROM AUTHOR]

Abstract: Global temperature rise over the long term will be proportional to the total amount of CO2 emitted. Any given probability of exceeding a targeted maximum temperature rise implies a maximum limit on the cumulative total of CO2 that can be emitted: a CO2 “budget”. This paper describes an approach to modelling cumulative emissions from light and heavy duty road transport from the present to 2050, focussing on the USA and Europe, and comparing the potential impacts of a range of technological and behaviourally-based abatement measures with such cumulative emissions budgets. The model shows that abatement measures would have a lower effect on cumulative emissions from 2000 to 2050 than on annual emissions in 2050, so that focussing only on annual emissions could be misleading. It shows that technological developments would be insufficient on their own to enable Europe and the USA to meet CO2 budgets for road transport. Behavioural changes, which potentially can be implemented much sooner, would be essential too. There is potential to keep European light duty emissions very close to CO2 budgets, and US light duty emissions not far above the least restrictive budget, but the model predicts that heavy duty emissions in both regions are likely to exceed their CO2 budgets. Deeper emissions reductions in other regions and sectors will be needed to compensate for this. Timing would be critical: for the greatest impact, behaviour change policies and interventions would need to be applied early and deeply. [Copyright &y& Elsevier]

Abstract: This paper compares spatial and seasonal variations and temporal trends in modeled and measured concentrations of sulfur and nitrogen compounds in wet and dry deposition over an 18-year period (1988–2005) over a portion of the northeastern United States. Substantial emissions reduction programs occurred over this time period, including Title IV of the Clean Air Act Amendments of 1990 which primarily resulted in large decreases in sulfur dioxide (SO2) emissions by 1995, and nitrogen oxide (NOx) trading programs which resulted in large decreases in warm season NOx emissions by 2004. Additionally, NOx emissions from mobile sources declined more gradually over this period. The results presented here illustrate the use of both operational and dynamic model evaluation and suggest that the modeling system largely captures the seasonal and long-term changes in sulfur compounds. The modeling system generally captures the long-term trends in nitrogen compounds, but does not reproduce the average seasonal variation or spatial patterns in nitrate. [ABSTRACT FROM AUTHOR]