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.

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.

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.

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.

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.

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.

Current atmospheric concentrations of greenhouse gases are projected to increase global temperatures by an additional 1oF in coming decades. Thus some degree of continued climate change is inevitable, despite efforts to reduce greenhouse gas emissions, but emissions reductions will aid in reducing the magnitude of that change and stopping human-induced increases in global temperatures.

One of the strongest pieces of evidence for human-induced climate change is the consistent rise in carbon dioxide (CO2) in modern times, as measured at the Mauna Loa Observatory in Hawaii, where CO2 has been observed since 1958. As of 2005, the concentration of CO2 in Earth’s atmosphere was about 378 parts per million (ppm).

There are six main greenhouse gases, the most common of which are carbon dioxide (C02), methane (CH4) and nitrous oxide (N20). These are all produced from human activity - C02 from transport and energy; CH4 mainly from animals burping out the gas as they digest their food; N20 mainly from agriculture such as the use of fertiliser and when animals urinate.

The oil sands make up about 2.5 per cent of Canada’s and less than one tenth of one per cent (0.06 per cent) of the world’s overall greenhouse gas emissions.

In 2007, Alberta became the first jurisdiction in North America to legislate greenhouse gas reductions on large industrial facilities. This legislation resulted in the July 1st deadline when Alberta facilities that emit more than 100,000 tonnes of greenhouse gases a year will be required to reduce their emissions intensity by 12 per cent. Industry is taking steps to emit fewer greenhouse gases.

Firms that have an emission intensity lower than their targets will receive credits that could be sold to those who are unable to meet their obligations. Credits could also be "banked" for future use. Firms that have an emission intensity that is above their target could use credits from previous years, or purchase credits from other firms that have a surplus.

The concentration of carbon dioxide is approximately 30 per cent greater than it was in the 18th century, before the industrial revolution. It has increased from around 280 parts per million (ppm) to approximately 360 ppm today. Although carbon dioxide comprises only 0.036 per cent of the air, its warming effect is significant. Methane levels have risen from a pre-industrial concentration of about 700 parts per billion (ppb) to 1700 ppb.

In 2001, Australia produced 528.1 million tonnes of carbon dioxide equivalent -- this was mainly carbon dioxide (69.9%) as well as methane (22.9%), nitrous oxide (6.3%) and other gases. Of Australia's total net emissions in 2001, the production of energy accounted for 68.0%, 19.5% came from agriculture, emissions from industrial processes contributed 4.6%, and waste emissions contributed 3.1%.