International. The ozone hole over the Antarctic region has shrunk this year by 30% from the record recorded in 2006, the European Space Agency (ESA) reported. According to measurements made by ESA's Envisat satellite, this year ozone loss peaked at 27.7 million tonnes, up from 40 million last year.
For scientists, the fact that the hole is lower this year is not a sign of a long-term trend but is due to natural variations in temperatures and atmospheric dynamics.
To know the loss of ozone, the surface and depth of the hole are measured. Layer thickness is measured in Dobson units. This year the area of the hole - where ozone is less than 220 Dobson units - is 24.7 million square kilometers, that is, approximately the surface of North America, while the lowest value of the ozone layer is around 120 Dobson units, ESA said.
