with this, we refer to CO2 = Carbon Dioxide and equivalent gasses that qualify for what we generally denominate "CO2e-Certificates" under the "Kyoto Protocol".

There are different gasses that contribute more or less to the Greenhouse effect and hence they receive more or less CO2e-Certificates for preventing or removing 1 ton of their CO2-equivalent.  1 ton of CH4 will e.g. contribute 23 times more to the Greenhouse Effect than 1 ton of CO2.  For this reason, a project preventing or removing 1 ton of CH4 will receive 23 CO2e-Certificates.

As scientific knowledge progresses, the Global Warming Potential factor per gas can evolve, CH4 used to generate only 21 CO2e-Certificates, but this has been moved upwards to 23 since 2008.

More and more gasses are being added under the Emission Trading Scheme.

There are different CO2e-Certificates: AAU's, CER's, VER's, Green/Black/Gray/White Certifictates,...

The way to calculate how many CO2e-Certificates
You start noticing that "Kyoto Protocol Consulting" is a business on itself, that demands follow-up and time.

The result of the Kyoto Protocol is :
  1. to go for a system that allows / oblidges the economy to take Greenhouse Gasses up in their decision making (globally CO2e still rise)
  2. transfer of money and technologies, from rich to poor countries, so they can develop straight to a Sustainable Economy and by-pass a Fossil Fuel Based Economy/Industrial Revolution
If we do not manage to keep the CO2e-concentration under 450 ppm in the atmosphere by 2015, the planet will start an era of self-heating, leading to "catastrophic" situations according to the IPCC.

You will often hear this: 20-20-20, referring to the Poznan - 2008 declaration whereby the European Union agreed to reduce CO2e-emissions by 20% by 2020 and have 20% of its energy generation coming from renewable energy sources in Europe.
This however oversees an important other figure that has been left out:
 * 20-20-20-0 : with the "0", referring to the fact that with this measure we would be able to reduce the Global Heating back to 0°C.  Our leaders have abandoned that goal.
 * 20-20-20-2 : with the -2, referring to the fact that by these measures we will be able to keep the Global Heating under 2°C, leading to "Manageable Climate Change scenario's, referring to the estimated casualties being below 1 billion people and Climate Change Adaptation, i.e. - frankly speaking - determining how much the west is going to pay for every person killed in often already poor regions that are going to be even harder affected by the Global Climate Destabilisation.  The IPCC unfortunately predicts that with the measures on the table now, we will overshoot the Peak Temperate - referring to the year in which the Planet must reach it's peak temperature after which it will cool down - because the measures to reduce Greenhouse Gas Emissions were not taken early enough nor by enough countries.
* 20-20-20+2 : referring to the Scenario's in which we enter + 450 ppm CO2 in the atmosphere, which will lead to a planet that will resemble to Tina Turner and Mel Gibson's Mad Max in a couple of decades.  For more :