The greenhouse gas estimates presented here are full fuel-cycle estimates, combining the three major greenhouse gases emitted by motor vehicles: Full fuel-cycle estimates include all steps in the use of a fuel, from production and refining to distribution and final use. This gives a more complete picture of the climate change impacts of using a particular fuel. Some greenhouse gases have greater impacts on climate than others.

Greenhouse gas emissions are gases that trap heat in the Earth's atmosphere. Without greenhouse gases the average global temperature would go from 59 degrees Fahrenheit to 0 degrees Fahrenheit. The most notable greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), halocarbons that contain fluorine such as hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), and sulfur hexafluoride (SF6) (EPA 2003c). Each greenhouse gas differs in its ability to hold heat.

Scientists know for certain that human activities are changing the composition of Earth's atmosphere. Increasing levels of greenhouse gases, like carbon dioxide (CO2 ), in the atmosphere since pre-industrial times have been well documented. There is no doubt this atmospheric buildup of carbon dioxide and other greenhouse gases is largely the result of human activities. It's well accepted by scientists that greenhouse gases trap heat in the Earth's atmosphere and tend to warm the planet.

Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2004. U.S. EPA, Office of Atmospheric Programs. EPA/430/R-06-002. April 15, 2006. This report presents estimates by the United States government of U.S. human-related greenhouse gas emissions and sinks for the years 1990 through 2004. The information provided in this inventory is presented in accordance with the Revised 1996 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories.

Landfill gas recovery projects provide a highly effective means of reducing overall greenhouse gas emissions from landfills, whether the landfill gas is combusted by flare, electricity generation equipment, or another end use system. By using the otherwise wasted methane contained in the collected landfill gas to generate electricity or directly as a fuel, fossil fuels such as oil and coal are displaced.

Natural gas is primarily methane, which is a major greenhouse gas. Methane is emitted directly to the atmosphere from sources such as leaks in natural gas wells and pipelines and is produced in landfills, sewage treatment facilities and livestock operations. Other major greenhouse gases, carbon dioxide and nitrous oxides are produced when natural gas is burned for heating and electric power production.

Major industrial sectors, including electricity produced by combustion, oil and gas, base metal smelters, iron and steel, some mining sectors, cement, forest products, and chemicals production contribute about half of Canada's greenhouse gas emissions that cause climate change. Industry produces about half of Canada's greenhouse gas emissions that cause climate change and our plan sets mandatory targets for them to reduce these emissions.

Carbon dioxide (the key factor in climate change) and other greenhouse gases come mainly from the exhaust pipes of cars, trucks and other vehicles, and from the stacks of power plants and industries that burn coal, oil, and gas. In Canada the biggest source of carbon dioxide is transportation -- approximately one-quarter of the total. Industries are not far behind contributing 19 per cent.

All Canadians need to get involved in reducing emissions of greenhouse gases that cause climate change, as well as air pollution. Making use of the Government's public transit tax credit and increasing your use of public transit to help reduce traffic congestion and air pollution in our cities, and greenhouse gas emissions that impact on our climate. Consulting the ecoENERGY for Personal Vehicles program to help you choose more eco-friendly vehicles.

By 2010, the Climate Savers Computing Initiative seeks to reduce global CO2 emissions from the operation of computers by 54 million tons per year, equivalent to the annual output of 11 million cars or 10–20 coal-fired power plants.5 Under the assumptions detailed below (see footnote No. 6), total power consumption for PCs shipped in 2010 will be reduced by over 50%, for a total savings of 62 billion kWh in 2010, worth more than $5.5 billion (at an average cost of $0.0885/kWh).

Businesses that take steps to reduce their greenhouse gas emissions are likely to see an increase in efficiency, helping them save money and setting the bar higher for their competition. Considering that most lawmakers and citizens believe regulatory limits on GHG emissions are inevitable, companies that are early to respond to climate change and pollution will have a technological and economical advantage over their competitors.

For the U.S., carbon dioxide released by burning oil, coal and natural gas makes up 82% of total greenhouse gas emissions (weighted by climate-change impact), according to the federal Department of Energy. The remainder is methane (9%, from landfills, coal mines, oil and gas operations and agriculture); nitrous oxide (5%, from burning fossil fuels and from certain fertilizers); refrigerants and other "engineered" chemicals (2%); and carbon dioxide from other sources (2%).

the country level, CAIT includes emissions of (1) CO2 from fossil fuels and cement (1850-2002), (2) CO2 from land-use changes (1950-2000), (3) and non-CO2 gases, such as methane (CH4) and nitrous oxide (N2O) (1990, 1995, 2000). CAIT also includes sector-level GHG data, broken down by energy (with five subsectors, such as electricity & heat), industrial processes, agriculture, land use change and forestry, waste, and international bunkers.

Based on 2002 data (the latest available), the U.S. is responsible for nearly 22% of the world's CO2 emissions from fuel-burning. Because fewer than 5% of the world's people are Americans, per capita we emit 5 to 6 times as much CO2 as the average non-American; historically, the disparity is even greater. (Carbon dioxide molecules persist in Earth's atmosphere for around a century, which means that our past emissions are causing climate change now and in the future.

When the ethanol component of E10 Unleaded is burned, the carbon dioxide it releases into the atmosphere is actually used by plants to grow, including the crops that can be used to create ethanol. This 'cycling' of carbon reduces the build-up of carbon dioxide in the atmosphere. The amount of greenhouse benefit varies depending on how the ethanol is produced and the crops used as feedstock.

Sooner or later, yes. Because CO2 stays in the atmosphere for about a century, simply freezing the annual emissions won't stop the atmospheric concentrations rising. To stabilize the atmospheric levels of CO2, be it at double, triple, quadruple preindustrial levels (or more), will eventually involve phasing out fossil fuels entirely. This is extraordinarily difficult.Fossil fuels are the basis of modern urban civilization.

Once emitted, GHGs can remain in the atmosphere for many years, from approximately 10 years to thousands of years, depending on the gas. This means that emissions from a long time ago are still in the atmosphere and still affecting the Earth's climate system. Countries in the developed world have been emitting substantial quantities of GHGs since the start of the industrial revolution in the mid-18th Century.

There are many actions that individuals can take to reduce greenhouse gas emissions. Please visit the “Take Action” to find out how. Government of Canada – One-Tonne Challenge - Frequently Asked Questions http://www.climatechange.gc.ca/onetonne/english/faq.asp copy; 2001 - 2005 New Brunswick Climate Change Public Education and Outreach Hub. All Rights Reserved.