Nutrient input ceilings are readily calculated by
subtracting the reduction requirements (CART) in the 2013 Ministerial
Declaration from the net nutrient inputs of each country and basin in the
reference period 1997-2003.
Following the same procedure, nutrient input ceilings can also be assigned
to shipping and other sources of airborne inputs.
sum of all nutrient input ceilings for a basin will be equal to MAI to that basin (Tables 4a and b).
information for this calculation was included in the background document for the 2013 Ministerial Meeting. However, detailed information was not provided
for calculating the nutrient input ceiling for the basin and nutrient combinations which do not have a reduction
requirement. For phosphorus, the nutrient input ceiling in these basins is simply equal to the net
inputs in the reference period, but for airborne nitrogen inputs reductions due
to implementation of Gothenburg protocol and regulations on shipping emissions
were taking into account in the 2013 Ministerial Declaration (see Background
document) also for the basins without nitrogen reduction requirements. Thus, in
order to meet the requirement that achieving the nutrient input ceiling should result in MAI for these
basin, the nutrient input ceiling will be slightly larger than reference inputs for the HELCOM Contracting Parties.
Table 4b: Nutrient input ceilings for phosphorus for all basins and countries