The ozone layer above Greece is showing signs of recovery and is likely to improve by the middle of the 21st century, scientists said yesterday. Alkiviadis Bais, associate professor of physics at the Aristotle University of Thessaloniki, said the first signs of recovery began appearing in the last three to four years. «We expect that by the middle of the century we will have a stabilization of the ozone,» Bais said. «The measures taken in the last 15-20 years have lead to an improving situation.» Scientists agree that the earth’s ozone layer is finally on the mend after decades of damage. However, the World Meteorological Organization (WMO) and the UN Environmental Program (UNEP) said yesterday that the protective layer, which filters dangerous solar radiation, was recovering more slowly than experts had originally hoped. Over huge areas of Europe, North America and Asia in the northern hemisphere the layer will be back to pre-1980 levels by 2049, according to experts.