Measuring carbon emission levels
Carbon dioxide released into the atmosphere by, for example, the electricity generation process is converted into carbon equivalent and then measured in metric tonnes.

Carbon emissions trading
As part of the European Union's action on climate change, in support of the Kyoto Protocol, the EU limited the amount of carbon dioxide that energy-intensive users are allowed to produce. Such heavy polluters now need permits to pollute and, if they haven't got enough and don't want to be faced with huge fines, the only alternative to investing big-time in more energy efficient machinery is to buy some more permits. This is known as the carbon emissions trading scheme.
See europa.eu.int for more information.

The Europe climate exchange is a commercial venture where organisations can now trade their carbon emissions. During October 2005, the volume being traded was running at about 2 million tonnes per day, with a price of 24 euros per tonne.

Kyoto protocol – action on reducing carbon emissions
By signing up to the Kyoto Protocol, the UK government committed to a 12.5% percent reduction in emissions of carbon by 2008-2012, relative to 1990 levels. In fact the UK government went even further than Kyoto and committed itself to achieving a carbon emission reduction target of 20% by 2010. (See the Department of Trade & Industry’s (dti) 2005 document “Energy – its impact on the environment and society” )

Based on progress so far, the UK government is anticipating a shortfall of 10 million tonnes in the 20% reduction it has set itself to achieve by 2010. This is separate from the legally binding Kyoto target of a 12.5% reduction by 2012.

Carbon dioxide parts per million
Scientists frequently use another measure of the pollution from carbon dioxide and other toxins. This is the parts per million (PPM) measure and represents a unit of concentration in a larger volume, such as the earth’s atmosphere or envelope of air. The levels in the atmosphere have risen from 290 ppm in the 19th century to 380 ppm in 2005. At the beginning of this year, Tony Blair asked a panel of scientists to give a maximum CO2 ppm figure for the world. They said 400 ppm. Any higher and we risked serious consequences for the health of the planet. Worryingly, on November 1st 2005, Claude Mandil, Executive Director of the International Energy Authority, IEA, said that 550 ppm was a much more realistic maximum, given the rate at which the developing nations, particularly China and India are ramping up their CO2 emissions level.

CO2 Measures Graph

Relationship between the two types of measurements
If we know the volume of air from which the carbon dioxide parts per million figure has been calculated, we can then work out the corresponding weight of carbon contained.

Ratio of carbon to carbon dioxide
People often use carbon and carbon dioxide (CO2) interchangeably. They are not the same and you can calculate the carbon content from a given amount of carbon dioxide by dividing the CO2 amount by 44/12 or 3.66 recurring.

Impact of UK government action on energy sources for generating electricity
One of the ways the government has been trying to reduce carbon emissions is by encouraging the use of clean(er) energy technologies such as renewables (solar, wind and wave) and combined heat and power (CHP). Renewables accounted for 3.6% of electricity production in 2004, or 15,000 GWh, while CHP accounted for 7% Wind accounted for 0.5% of production although it accounted for 1.5% of production capacity.