The amount of the participation which is asked to participants, i.e., 18 €, should be sufficient to mitigate the whole greenhouse emissions due to this conference, whose cost is estimated to ~ 16 000 €. The 18 € amount is based on 900 participants.

This amount was estimated from an early estimation of GHG emissions, which is a bit less than the final estimation.

You may find below some detailed computations on how the cost of mitigating these greenhouse emissions is made.

Emissions due to transport, i.e., venue to Lille, France, are mostly due to planes, thus CO2 emission will stay in upper atmosphere and will spread over the world. This international source of CO2 will be compensated by the international project of taking part to reforest a national park in Argentina. Other emissions, as they are more local to Lille or France, will be compensated by planting trees in France.

We then separate our forthcoming computations in two parts:

  • emissions due to transport are estimated to 1081 tons equivalent CO2, as an average. Significant uncertainties (10% due to our way of computing distances and 20% more due to distance to CO2 emission conversion factors) increase this estimation up to 1427 t eq. CO2,
  • other emissions are estimated to 122 t eq. CO2, as an average, which needs to be increased by the 50% uncertainty, i.e., up to 183 t eq. CO2.

Concerning transport, the Argentina park captures 250 t CO2/ha of forest as an average. Applying a usual 25% uncertainty factor leads to 7.6 ha of forest we need to plant. Each ha contains 100 adult trees, or 1000 young trees. We then need to plant ~ 7 600 young trees. From the previous VPPC'10 experience, each tree cost 0.8 €. It was in 2011, but Argentina is known to have a huge inflation of prices, from the official 9%/yr to the double from more realistic sources, leading to 30% up to 65% inflation in 3 years, as we will buy those trees after the conference, i.e., in 2014. We will use an in-between 50% value of inflation, thus each tree will cost 1.2 €. The total cost for transport is then 9132 €.

Concerning other emissions, each oak may capture 4.9 tons of CO2 per life (120-150 years). This lifetime scale is what we need to compensate CO2 emissions, which stay in the atmosphere approximately 100 years . Applying the usual 25% uncertainty factor leads to 3.6 t CO2 / tree. We thus need to plant 51 trees. Each tree costs 134 €. The cost for other emissions is then 6834 €.

Total cost for mitigating our emissions is then 15966 €. This amount has to be divided by the possible number of participants, i.e. 1000 participants on average with a 10% uncertainty. Dividing the total cost by 900 participants leads to 17.74 € per participant, which is rounded to 18 €.