MercoPress. South Atlantic News Agency

Ozone hole growing faster.

The ozone hole has grown more rapidly than usual during the last two weeks compared to the same period a year ago according to the latest World Meteorological Organization, WMO, report.

Currently the ozone layer hole appears to be 25 million square kilometres in area, 10% below the record size of mid September 2000 when it reached 27 million square kilometres. The ozone mass deficit (a measure of the depth of the ozone hole) has reached 50 million tons, which "is also 10% below the record set in mid September 2000".

"The size, depth and persistence of the ozone hole are expected to vary substantially from year to year and are strongly influenced by meteorological changes, as was the case in 2000 when the ozone hole was the largest on record and in 2002 when it was the smallest since 1988, a single year cannot be used to infer a general trend in the ozone hole parameters", states the WMO report.

Barbara Tapia a WMO expert said that even when current satellite measurements show the ozone' hole growing, "it's still far behind three years ago".

The ozone layer at an altitude of 20/25 kilometres acts as a natural filter for the UV rays that are particularly harmful for living beings.

Ms. Tapia explained that at this time of the year, the austral winter, temperatures are particularly low in Antarctica and can drop to an average 78 Celsius below zero, thus generating the appearance of polar stratospheric clouds.

These clouds in combination with the chlorofluorocarbon, CFC, produce the chloride monoxide that attack and destroy ozone.

The fact that temperatures in the Antarctic during the last few weeks dropped to minus 93 Celsius has generated "the appearance of more polar clouds than usual and the chemical reaction has accelerated the thinning of the ozone layer", said Ms. Tapia.

"Temperatures remain sufficiently low for polar clouds to cover about 70% of the vortex area, down from 80 to 90% reported in mid August. This area will further decrease in the coming weeks as the sun continues to rise and to warm the stratosphere over Antarctica".

Towards the end of 2003 with the coming of the summer in the southern hemisphere clouds will dilute and "the hole will become smaller as happens every year".