Time Series Properties of Carbon Emissions in the U.S. States for the Period 1961-2001

Raupach et al. (2007) show  that the growth of carbon dioxide (CO₂) emissions from fossil-fuel burning and industrial processes has been accelerating on a global scale, and at a higher rate than anticipated by the Intergovernmental Panel on Climate Change (IPCC) in the late 1990s. They also observed that neither developed nor developing regions in the world show signs of decarbonizing their energy supplies.  In 2007 the U.S. Supreme Court directed the EPA to decide whether greenhouse gases, especially CO₂ from burning fossil fuels, pose a threat to public health and welfare because they are warming the Earth.  If their decision is positive, there would likely be broad economic and environmental ramifications. In particular, it would mean that CO₂ and other greenhouse gases would be regulated under the Clean Air Act.  Considering this, it is therefore important to better understand the long term nexus between carbon dioxide emissions and economic growth. In this paper we present evidence on the time series properties of carbon emissions from all US states for the period 1963 to 2001. Further, we disaggregate total carbon emissions to its coal, oil, and gas components.  We do this to analyze the source of the upward trend in overall carbon emissions.  We also investigate how the emissions data relate to income and population growth.   Our findings suggest that most sources of carbon emissions are stationary for the majority of states when scaled by income.  Data are found to be only occasionally stationary when scaled by population, and nearly never in levels.