How Much Do We Emit?

  • Over half of the CO2 emissions caused by human activity during the past 30 years comes from burning fossil fuels. The rest is predominantly due to land-use change, especially deforestation.
  • The U.S. presently emits more greenhouse gases per person than any other country, accounting for roughly 22% of global emissions, with only 4.6% of the world’s population.
  • U.S. per capita emissions are roughly 20 metric tons of greenhouse gases per person each year.
  • Electricity production is the leading source of carbon dioxide emissions from fossil fuel combustion.
  • U.S. carbon dioxide emissions have grown by more than 16% since 1990 and the Department of Energy now projects that they will increase by another 20% by 2020.

A Growing Concern

  • Continuation of historical trends in greenhouse gas emissions will result in additional warming over the 21st century, with current projections of a global increase of 2ºF to 11.5ºF by 2100, with warming in the U.S. expected to be even higher. For a comparison, global temperatures during the last ice age (about 20,000 years ago) were only 9°F cooler than today, but that was enough to allow massive ice sheets to reach as far south as the Great Lakes and New York City.
  • Rising air temperatures have already resulted in the retreat of mountain glaciers, reduced snow-cover, earlier snow melt, rising sea level, and the movement north of some species habitat.
  • According to the EPA, a two-foot rise in sea level would eliminate 17-43% of U.S. wetlands (with more than half the loss taking place in Louisiana). Furthermore, it would eliminate approximately 10,000 square miles of land, an area equal to the combined size of Massachusetts and Delaware.
  • Developing nations, who are less equipped to handle the impacts of climate change, will be among the most effected by the adverse impacts of climate change, including decreased access to water sources, further reductions in viable farmland and disease outbreaks.

The role electricity generation plays

Electricity generation is responsible for 23% of greenhouse gas emissions and the demand for electricity is growing rapidly. As of the year 2006, in the United States, generation of electricity was responsible for 23% of total GHG emissions; transportation 22%, industry 20%, commercial sources 18%, and residential sources 17%. By 2020, the world will consume 57% more electricity in 2020 than it does today, according to the US Energy Information Administration.

The role transportation plays

CO2 emissions from transportation also make a significant contribution to the greenhouse gas emissions released today. According to the most recent data, 14% of the world’s human activity-related emissions come from transportation.  It is undeniable that transportation is essential to our way of life, and emissions resulting from the transportation sector are still on the rise. According to the EPA, this trend may be attributed to two related causes: the average fuel economy of passenger vehicles in the U.S. has only risen slightly, while the number of miles driven by Americans has increased more rapidly. The average passenger vehicle, driven 12,400 miles per year emits about 10,735 pounds of CO2 per year.

For a brief overview of international and regional greenhouse gas policy and initiatives visit The Pew Center for Global Climate Change.