Every day, all over the world, we participate in activities that produce global warming gases. How much pollution are we generating? The global greenhouse gas emissions counter on the collage started from zero on January 1st, 2007 and increases at a rate of approximately 1,268.51 tonnes CO2-equivalent per second. We refer to global emissions in metric tonnes (rather than short tons, with which we’re more familiar in the US) because metric units are the standard for global reporting and analysis.
Wondering what contributes to the world emissions of greenhouse gases? This pie chart shows that energy use is the most significant contributor to global greenhouse gas emissions, encompassing electricity, heat, fuel combustion, transportation, and a portion of manufacturing and construction. Agriculture at 17% is the next largest contributor.
Source: World Resources Institute (WRI): 2000 World Million Metric Tonnes (MMT) CO2 Eq.
What is America's contribution to world emissions? The pie chart for 2005 US emissions shows that electricity and transportation are the two biggest contributors of greenhouse gas emissions. Industry is the third biggest source with agriculture, commercial, and residential emissions comprising the remaining greenhouse gases.
Source: US EPA: 2005 US Million Metric Tonnes (MMT) CO2 Eq.
If we assign the emissions from electricity to the sectors that consume it, the industry, residential and commercial sectors, we see that these three sectors make up more than 60% of our greenhouse gas emissions. This shows us that even though we don’t usually see the power generating facility or refinery operating next to our house or workplace, our consumption of electricity and fuels for heating have a major impact on greenhouse gas emissions. The Alliance’s Black Balloon ads illustrate this very effectively.
Source: US EPA: 2005 US Million Metric Tonnes (MMT) CO2 Eq.
Note that the figures above don't take into account the absorption of greenhouse gases by carbon sinks, which are elements of our ecosystems that remove CO2 from the atmosphere (like forests). When these sinks are included the total or net emissions are lower by around 10%.
How does America stack up against the rest of the world? In 2000, the latest year of country emissions rankings, the US was the biggest country emitter of greenhouse gases with China trailing in second place. Experts, however, believe that sometime in 2007, China will overtake the US. It is particularly interesting that China is the second biggest emitter and India is the fifth biggest (EU is counted as one country) but respectively have the 100th and 147th highest per capita emissions among ranked countries. So in this ranking, each American has 5 to 10 times the greenhouse impact of a Chinese or Indian citizen.
What does CO2 eq mean?
- The standard method of counting greenhouse gas emissions is defined by the Intergovernmental Panel on Climate Change (IPCC) with 6 types of greenhouse gases.
- Each gas is assigned a 100-year Global Warming Potential (GWP) that says how much warming the gas produces compared to carbon dioxide; the bigger the number, the greater the warming. The following are the most important of the global warming gases. They are listed by name and chemical symbol or acronym, along with their GWP.
- Carbon dioxide (CO2), GWP = 1
- Methane (CH4), GWP = 21
- Nitrous oxide (N2O), GWP = 310
- Perfluorocarbons (PFC), GWP = 6,500 to 9,200
- Hydrofluorocarbons (HFC), GWP = 140 to 11,700
- Sulfur hexafluoride (SF6), GWP = 23,900
- The emissions of each gas are multiplied by their GWP to vie the carbon dioxide equivalent emissions, or CO2 Eq.
How did we calculate the counter?
The global greenhouse gas counter was calculated using the World Resources Institute Climate Analysis Indicators Tool (CAIT) version 4.0 (Washington DC: World Resources Institute 2007), available at http://cait.wri.org/.
We started with the CAIT world emissions figures for 2000 for all gases and then applied the CAIT energy projection for 2002-2007 of average annual growth of 2.7%. We applied the same growth rate to all emissions (not just energy) and assumed similar growth from 2000 to 2002. The resulting projected 2007 global emissions is 40,004 MMT CO2 Eq. or 1,268.51 tonnes CO2 Eq./sec.
