A recent graph created by Ecofys, a renewable energy and climate policy-consulting group, details the specific sources of global greenhouse gas (GHG) emissions. From a quick glance at the graph, you would notice that carbon dioxide emissions amount to an overwhelming 76% of all total greenhouse gas emissions, that fossil-fuel related emissions are approximately equally distributed amongst coal, natural gas, and oil, and that emissions from agriculture, land use change, and energy supply account for more than one-third of all total emissions. What is not evident from the graph, however, is the changing landscape of American energy sources.
For many decades, coal remained the top energy source for generating electricity in the United States. As recently as 2001, coal made up 51% of American electricity production. Because coal has the highest carbon content of all three fossil fuels, GHG emissions from coal represented 28.3% of all total GHG emissions in the United States in 2010.
When compared to the original graph, emissions from coal in the US are a greater proportion of GHG emissions than the globe’s percentage of 25%. However, the strength of the coal industry is waning in the wake of a natural gas energy boom in the United States.
Using natural gas as a source for electricity nearly doubled since the start of the 21st century; increasing from approximately 17% to over 30% of total fossil fuel use. From an emissions standpoint, this change is highly beneficial as natural gas emits half the amount of carbon dioxide compared to coal; 0.4 tons/Megawatt hours and 0.9 tons/Megawatt hours, respectively. The United States can take advantage of this newly abundant energy source to produce electricity, and in turn, decrease both domestic coal consumption and carbon dioxide emissions.
However, the United States must invest in clean energy sources to supplant fossil fuels in general. Natural gas still produces methane, an even more potent greenhouse gas, and global reliance on coal is only increasing with the industrialization of many developing countries. Research in new energy sources such as fusion and continued development of renewable energy sources like solar and wind must continue for the United States to reduce GHG emissions dramatically and become more energy independent.