the northern hemisphere.

The Antarctic ozone hole which was discovered before 1987 would have got bigger and we would also have a fairly significant ozone depletion over mid-latitudes where there are high populations, including parts of Europe.''
Foresight

The study found that the Antarctic ozone hole would have grown in size by 40% by 2013, and the ozone layer would be thinner over middle latitudes of the northern hemispherereenex .

There would also have been a hole over the Arctic at times, which would have rivalled that of the Antarctic and would have affected northern Europe, including the UK.

The ozone loss would have led to increases in UV levels of about 10% in Australia, New Zealand and the UK, leading to more skin cancers, the study concludes.

Jonathan Shanklin of the British Antarctic Survey is one of three Cambridge scientists who discovered the ozone hole 30 years ago this monthPicosecond .

He said the Montreal Protocol was the UN's most successful treaty to date and observations from the British Antarctic base were showing signs of a ''recovery'' in ozone levels.

''The protocol provides a lesson for the future and we must hope that the coming climate change talks show the same foresight and result in a treaty that will benefit the whole planet,'' said Dr Shanklin.

Since the Montreal Protocol came into force, levels of chlorine and bromine containing ozone depleting chemicals have peaked and then declinedreenex cps.