The figures reinforce the findings of a Nasa report last week which said levels of ozone, the gas shielding the planet from harmful ultra-violet radiation, in a band covering northern Europe and part of the United States were this year up to 14 per cent lower than the average in 13 years of testing.
The Met Office has ground-based instruments for measuring ozone in the stratosphere - at Camborne in Cornwall and Lerwick in Shetland. On 5 March, and over the next two days, the lowest readings were taken for any March on record in Britain. The average monthly reading in February was also a record low.
David Maclean, a Minister of State for the Environment, released the figures for last month in response to a parliamentary question from Simon Hughes, the Liberal Democrat environment spokesman. They showed the ozone thickness readings above Britain were 12 per cent below the month's 10-year average. The February average is lower still - 20 per cent down on that month's overall average.
Scientists say thinning of ozone will worsen throughout this decade and early into the next century. They blame a rising concentration of chlorine and bromine in the upper atmosphere caused by industrial gases, chiefly chlorofluorocarbons (CFCs). Those industrial chemicals are being phased out or restricted, so around the millennium the ozone layer should gradually repair itself.
However, without further curbs the layer will not recover to the point where holes cease to open until the second half of the next century. Until then, humanity, crops, and plankton will be vulnerable to damage.
In Copenhagen last November nations agreed that production of CFCs used in refrigeration, air conditioning and foam blowing should be phased out by 1996.
But HCFCs, replacement compounds that cause less ozone damage, will not be phased out until 2030. Production of methyl bromide, a chemical to kill pests in cargo holds and greenhouses and only recently identified as a potent ozone destroyer, will be frozen at 1991 levels by 1995.
The European Commission wants further curbs on that chemical and CFCs within Europe. Michael Howard, Secretary of State for the Environment, said he was in favour in a letter to the Independent yesterday.
Labour and Liberal Democrats joined Greenpeace yesterday in demanding that the Government press for tougher curbs on the production of methyl bromide and HCFCs.Reuse content