Additional explanation about using the Greenhouse Emission Model (GEM)

On 6 July a message was posted about a temporary solution for the soil-bound crop scenarios of the GEM. This message caused some confusion. Additional explanation is therefore in order:

  • According to the Guidance Document on Protected Crops, applicants are required to calculate emissions from protected crops with a model. GEM is one model that can be used for this purpose.
  • However, GEM scenarios for soil-bound, protected crops have been shown to be very sensitive for the testing date. This is inconvenient because a dosing date must be chosen in the model. For the initial calculation, based on a number of test calculations by WUR with two different substances, the dosing date of 30 May was found to be the best option.  Because there are a number of uncertainties, a safety factor of two is being used for the time being.
  • If the soil-bound scenario of GEM is used as the first tier (this is the first sieve) the products that pass through are certainly safe.
  • For products that do not pass through the first tier, GEM can also be used with additional calculations for the second tier (i.e. the second sieve). In that case, applicants can make their own calculations, supported with reasons, for the various dosing dates during the relevant period. Consequently, the safety factor of two can be dispensed with.

This procedure will remain in force until a new version of GEM becomes available.

As noted above, applicants can also use their own calculations with a different model for the second tier and are not obliged to use GEM.