Ozone layer recovered: Happy or worried?

The announcement released last year by the WMO World Meteorological Organization about the ozone layer's tendency to shrink has made environmental activists happy. But a group of scientists argue that this event might be the same as Reconstruction.

Ozone floor perforation: People can be "cooked nine"

The world began to pay much attention to the ozone layer since 1985, when scientists discovered that the armor protecting the Earth had a hole above the Antarctic. Ozone in the stratosphere of the atmosphere plays a vital role for the environment and humans, as it helps prevent most harmful ultraviolet radiation from the Sun. Without protective ozone, we will get sunburn in just 5 minutes outdoors.

Because of this awareness, the international community has tried to eliminate ozone depleting substances. And as a result, the ozone layer is looking smaller and smaller. On September 16, 2009, the ozone layer hole was measured at 24 million square kilometers, much smaller than the measured figure in 2008 of 27 million square kilometers. Scientists also predict that the ozone layer can fully recover after more than half a century.

Recovery ozone layer: Pollution, warming and melting ice

Should be happy, a team from the New Zealand National Water and Atmospheric Research Institute is concerned. Their computational model shows that, in combination with climate change, the ozone layer's recovery in the atmosphere can increase the amount of ozone near the ground, especially in the southern hemisphere.

If above, ozone is a protector, when near the ground, ozone is a threat. Prolonged exposure to ozone with concentrations greater than 40ppbv (parts per billion) can damage human health, reducing crop yield. The common ozone concentration in the most heavily contaminated areas of the northern hemisphere today is 50 - 80ppbv, while in the southern hemisphere is 25 - 35ppbv.

The ozone layer above the Antarctic.(Photo: Bee)

In the future, the average ozone concentration in the air near the ground will increase by about 15-20%, in particular, some places may nearly double when the ozone layer in the atmosphere recovers.

The reason is that the change in atmospheric circulation due to climate change will make ozone-rich gas masses from the stratosphere move faster and stronger to the lower layer, increasing the amount of ozone near the ground. The worst affected will be areas outside the tropics in the southern hemisphere. Ozone is a powerful greenhouse gas, so increasing ozone concentration near the ground also contributes to the speed of global warming.

A study by the University of Cambridge (UK) showed that ozone layer holes helped isolate Antarctica, sheltering this icy land from the effects of greenhouse gases. Along with many other factors, the recovery of the ozone layer can cause one third of Antarctica to melt.