Well as you ask, we are currently using the method below. We think it makes sense and is affordable, but we will review it on a regular basis and adjust as necessary.
Your secondary footprint element is based on this Government report issued by the Government in 2012.
The most recent factor for carbon emissions associated with clothing is 0.29kgCO2 per £ spent.
For every £100 spent this would equate to 29kg CO2.
We are basing our calculations on a spend of £300/year using this factor.
How is Dopplle paying the carbon offset? Here are our most recent Carbon Offset Certificates.