Smaller emissions from landfills than previously estimated

Landfills liberate the greenhouse gas methane (CH ₄ ), which contributes to the greenhouse effect and is included in the obligations in the Kyoto protocol. Methane is created in deep layers of the landfills, by the decomposition of biological waste without a supply of oxygen.

In 2005, Statistics Norway took over the operative responsibility for the model that estimates emissions of methane from landfills. In that connection, Statistics Norway examined the figures on waste amounts from 1945 to the present, and found a basis for making changes. In agreement with the Norwegian Pollution Control Authority, the degrading time for some waste types has been adjusted. Statistics Norway has also collected updated figures from the Norwegian Pollution Control Authority on amounts of methane recovered. We regard the emission figures presented to now be considerably better than previous figures. The calculation model constitutes a part of the emission accounts for greenhouse gases and other air pollutants, prepared by Statistics Norway and the Norwegian Pollution Control Authority.

Changes cause lower figures

To examine the effect of measures, it is important to have calculations that give reliable figures. Relatively high uncertainty is attached to calculations of methane from landfills, whilst also being an important source of Norway's greenhouse gas emissions. Because of this combination of importance and uncertainty, a great deal of resources have been used during recent years on improving the figures.

Towards the end of 2004, the Norwegian Pollution Control Authority updated the method and factors for estimating emissions of methane from landfills. This reduced this source's contribution to total greenhouse gas emissions from 7 to 4 per cent of Norway's total emissions in 2000 ( read more ). The revision recently carried out by Statistics Norway has further reduced the share to approximately 3 per cent. The revision has been performed for all years. Estimating methane emissions from landfills is complicated, and new knowledge may cause further revisions in the future.

Major reduction in methane emissions

As it appears from the table, methane emissions from Norwegian landfills were reduced by 30 300 tonnes in 1990, whereas the emissions in 2004 were 25 700 tonnes lower. This implies that estimated methane emissions from landfills have been reduced by approximately a quarter. As CO ₂ equivalents, the figures for 1990 and 2004 have been reduced by 637 000 and 539 000 tonnes respectively, which corresponds to about 1 per cent of Norway's total greenhouse gas emissions. The new calculations show less of a decline in emissions from 1990 to 2004 (see the table below). If the decline continues to be so low in the Kyoto period 2008-2012, it will be more difficult than previously assumed to meet Norway's obligations in the Kyoto protocol.