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The ozone layer over Norway has stabilized

Halo rundt solen
Foto: Ingunn Trones, NILU

The ozone layer over Norway appears to have stopped thinning. At the same time, however, NILU measured record low seasonal levels of ozone last winter.

The ozone layer protects all life on Earth from dangerous UV radiation from the sun. NILU monitors the ozone layer over Norway in a programme financed by Klif, the Climate and Pollution Agency.

NILU’s 2010 data confirm a positive trend that has been seen over the last decade. The ozone layer over Norway appears to have stabilized after having reached its thinnest level in 1998, according to NILU senior scientist Cathrine Lund Myhre, manager of the ozone and GHG monitoring programme in Norway.


  • 2010 was a year with generally high ozone values above Norway.
  • Measurements of ozone profiles and analyses of stratospheric conditions indicate that there was a short period, until mid-February, during which there was chemical ozone destruction.
  • The dynamic situation changed after mid-February and resulted in very high ozone values during the late winter and spring months.
  • The total decrease in the ozone layer from 1979-1997 above Oslo was 5.7 %, while it was 5.8 % above Andøya.
  • The strongest decrease occurred during the spring months, with an 8.3 % decrease above Oslo, and an 8.4 % decrease above Andøya.
  • There have been no significant changes in the ozone layer over Norway since 1998.
  • Estimates suggest that there has been a small increase in the ozone layer of 1.8 % above Oslo and 0.6 % above Andøya. However, these changes are not statistically significant.
  • The ozone layer above Norway has stabilized.