GWP – What is it?

‘Global warming potential’ (GWP) was developed by the IPCC to allow comparisons of the global warming impacts of different gases. It is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO₂)- CO₂e is therefore the calculated sum of a number of gases. The science community, IPCC, recommend the global warming potential from materials will on average be calculated to ‘100 years’, and this is what our system solution is based off.

It is estimated about that 50% of CO₂e increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within the next few centuries. The remaining 20% may stay in the atmosphere for many thousands of years.

The GWP for a mixture of gases can be obtained from the mass-fraction-weighted average of the GWPs of the individual gases. So, a substance’s GWP does depend on the number of years over which the potential is calculated. A gas which is quickly removed from the atmosphere may initially have a large effect, but for longer time periods, as it is removed, it becomes less important. Here are some examples:

Methane has a GWP potential of 34 over 100 years (GWP100 = 34), or 86 over 20 years (GWP20 = 86).

Sulfur Hexafluoride has a GWP potential of 22,800 over 100 years but 16,300 over 20 years

(Source: IPCC Third Assessment Report).

Therefore, the GWP value depends on how the gas concentration decays over time, in the atmosphere. This is often not precisely known so the values should not be considered exact. For this reason, when quoting a GWP it is important to give a reference to the calculation; In our case, we use the 100 years. Furthermore, development of technology and knowledge in the years to come will lead to a more sophisticated breaking down the GWP at a product level, but there is not enough reliable, accurate data available today.

However, it is possible to provide different metrics with our software system, based on a limited number of years impact. Please contact us for further details on this.