Professor Hans Joosten:

The second question related to the aims that are being put forward. We must remember that the IPCC in 2018 calculated that to reach the Paris Agreement goals, we would have to reduce emissions, and it specified that as 100% with respect to CO2, 50% to methane and 20% to nitrous oxide. The aims with respect to methane and nitrous oxide are all about food security. We cannot have rice or have ruminants grazing without methane emissions. If we push back methane emissions to zero, that will simply mean that we will have stopped eating rice, the most common food worldwide, and using ruminants for food, which is necessary in large parts of the world where only grass is available.

Nitrous oxide is a product of fertilisation. If we stop using artificial fertiliser or fertilisation completely, that will simply mean cereals will not have enough protein to be able to make bread, and that is what is behind these limited reductions with respect to methane and nitrous oxide. Therefore, the IPCC has stated we should focus on CO2 because that is the easiest goal to achieve while guaranteeing food security. The European Union has subsequently said we want to reach full climate neutrality and we have seen increasing aims, such as shortening the period from 2050 to 2045 or 2040. These are all different aims, formulated at different political levels, that we have to keep in mind.

With respect to the emission reduction effect of rewetting, we have to keep in mind that various peatlands do not have the same emissions. Deeply drained peatlands have much higher emissions than shallowly drained peatlands, so if we rewet the latter, it will lead to fewer emission reductions. These differentiations have been acknowledged by the IPCC in the report we wrote in 2014, where we identified various land use types for which different emission factors apply and for which different emission reductions can be calculated.