Bridges Trade BioRes • Volume 6 • Number 15 • 8th September 2006

Ozone Layer Recovery Likely to be Delayed

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A major new report predicts that recovery of the depleted atmospheric ozone layer will probably take longer than previously expected.

The document, produced by a panel of 250 experts on ozone depletion, states that the ozone layer over Antarctica will not be fully restored until between 2060 and 2075 - as much as 10 to 25 years later than earlier research had suggested.

Ozone recovery in other global regions will also be slower than previously believed. In 2049, chlorofluorocarbon (CFC) concentrations could return to pre-1980 levels over Europe, North America, Asia, Australia, Latin America and Africa - five years later than a 2002 report had predicted.

The findings have been produced by the Scientific Assessment Panel to the Montreal Protocol on Substances that Deplete the Ozone Layer - the treaty intended to phase out production of ozone-depleting substances.

The report, entitled “Scientific Assessment of Ozone Depletion: 2006,” suggests that two major factors are behind the delayed recovery. Firstly, there are signs that some kinds of CFCs not previously banned by the Protocol are still being used. Secondly, scientists now predict increased production of HFCF-22, a CFC substitute that still causes some ozone depletion.

“The delayed recovery is a warning that we cannot take the ozone layer for granted and must maintain and accelerate our efforts to phase out harmful chemicals,” said Achim Steiner, executive director of UNEP.

The Protocol does however appear to be having some effect in decreasing the concentration of ozone-depleting substances - such as CFCs and methyl bromide. Compared to peak levels in 1992-1994, there are now lower concentrations of these substances in the troposphere (the lowermost portion of the Earth’s atmosphere), and compared to 1990 levels, also lower concentrations in the stratosphere (which sits directly above the troposphere and contains the ozone layer) .

The full report will be released next year.

To access the executive summary of the “Scientific Assessment of Ozone Depletion: 2006,” visit: http://ozone.unep.org/Publications/Assessment_Reports/2006/Scientific_Assessment_2006_Exec_Summary.pdf

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