Fossil fuels and carbon emissions

Posted: 23 November 2007

Fossil fuels account for some 80 per cent of the world's primary energy consumption and supply roughly 90 per cent of the world's commercial energy. By 2010, global energy consumption will have risen by almost 50 per cent from 1993 levels, and unless successful efforts are made to reduce them, annual CO2 emissions will rise by the same proportion. The developing nations' share of commercial energy consumption is expected to grow from one-third to nearly 40 per cent by this date.

Since 1751 roughly 315 billion tons of carbon have been released to the atmosphere from the consumption of fossil fuels and cement production. Half of these emissions have occurred since the mid 1970s. The 2004 global fossil-fuel CO2 emission estimate, 7910 million metric tons of carbon, represents an all-time high and a 5.4 per cent increase from 2003.

Globally, liquid and solid fuels accounted for 77.5 per cent of the emissions from fossil-fuel burning in 2004. Combustion of gas fuels (e.g., natural gas) accounted for 18.1 per cent (1434 million metric tons of carbon) of the total emissions from fossil fuels in 2004 and reflects a gradually increasing global utilization of natural gas.

Emissions from cement production (298 million metric tons of carbon in 2004) have more than doubled since the mid 1970s and now represent 3.8 per cent of global CO2 releases from fossil-fuel burning and cement production. Gas flaring, which accounted for roughly 2 per cent of global emissions during the 1970s, now accounts for less than 1 per cent of global fossil-fuel releases.

  • Energy-related emissions account for more than 80 per cent of the CO2 released into the atmosphere each year.

  • If all economically recoverable conventional fossil fuel reserves were burnt over the next 100 years, this would lead to long-term global warming of well over 3.5°C.

  • Policies to promote greater energy efficiency could reduce the rise in energy use between 1993 and 2010 to 34 per cent, with emissions increasing 36 per cent. More aggressive policies could cut the growth rate still more.

  • Deforestation is the other human activity which increases carbon emissions, but fossil fuel emissions have exceeded deforestation emissions since the 1920s (see graph).

CO2 emissions graph
CO2 emissions graph
Graph shows the progress of CO2 emissions created from consumption and flaring of fossil fuels from 1980 to 2002. Indicates that Eastern Europe and Former Soviet Union is the only region to have a reduction.

  • Coal is by far the most prevalent fossil fuel. Based on static reserves, the world has enough coal to last 450 years, whereas oil could run out in 45 years and natural gas in 65. Petroleum production seems likely to peak by 2015.

  • Coal generates more than 70 per cent of the electricity in China and more than 60 per cent in South Asia, and electricity demand is rising at 6 to 7 per cent per year in these regions, which may result in a doubling of CO2 emissions there between 1990 and 2010.

  • Per capita energy consumption - and carbon emissions - are many times higher in poor countries than in the richest.

CO2 per capita graph
CO2 per capita graph
Historically the developed countries of the world have emitted most of the anthropogenic greenhouse gases. The US emits most in total, and is one of the countries with highest emissions per capita. China is the second largest emitter, but has very low emissions per capita. Over the last 20 years, industrial development has led to a rapid rise in the volume of emissions from Asia, but on a per capita basis, emissions in this region are still at the bottom of the global scale.

  • At present, two-thirds of primary energy is dissipated in the conversion to useful energy, and further losses occur in the delivery process.

  • Over the next 20 years, the amount of primary energy required for a given level of energy services could be cost-effectively reduced by about a third in industrialized countries, and by more in transition and developing economies.

  • With less than five per cent of world population, the United States uses 26 percent of global oil, 25 percent of the world's coal, and 27 per cent of the world's natural gas. It is the single-largest source of carbon from fossil fuels-emitting 24 percent of the world's total.

  • US automobiles (more than 128 million, or one quarter of the world's cars) emit roughly as much carbon.

  • Natural gas has become the fastest growing of all fossil fuels, representing nearly 24 per cent of the world's energy consumption. But annual growth rates of two per cent in this sector pale in comparison to alternative sources such as wind.

  • Improved technology could considerably reduce the amount of pollutants and greenhouse gases emitted in the combustion of coal and liquid fuels. The US Department of Energy's Vision 21 systems, using low-polluting combustion, gasification, high-efficiency furnaces and heat exchangers, and other developing technologies such as CO2 capture and recycling, would release no net CO2 emissions and have no adverse environmental impacts.

    See also: Fossil Fuels and Climate Protection - The Carbon Logic. A report by Greenpeace International.