Rainfall, Cloud Dwelling Bacteria and The Ozone Hole

Chris - In 1985, you discovered the hole in the ozone. How did you make that discovery?

Brian - We had been measuring the ozone since 1957, so we had already established the climatology of the ozone - what the ozone does season-by-season, day by day. We got used to what it looked like, so when we saw the pattern changing in the late 1970's, early 1980's, we knew something was happening.

Catherine - What does the ozone layer do on this planet normally?

Brian - It absorbs ultraviolet light (UV) from the sun. UV is dangerous for most living things. It can damage cells, so it can damage skin and crops. We can actually monitor the ozone layer by looking at this UV light. Because the ozone absorbs it, all we have to do is look at the UV coming down from the sun. If there is a lot getting through, there can't be much ozone.

Catherine - What area of the world has problems with its ozone layer?

Brian - Every area of the world has problems. Because we saw it in Antarctic and politicians took some action about it, ozone depletion over most of the world is relatively mild. It's a real problem in the Polar regions and particularly in Antarctica. We got a lucky break. Antarctica is the last place we expected to see the results of man-made pollution when there aren't too many people living there. But if the hole was over more populated areas, we would be in trouble.

Chris - Why is it in Antarctic?

Brian - During long winter months in the Antarctic, you get several months of complete darkness. Because it's dark, the atmosphere radiates infrared radiation into space, and it gets cool -the stratosphere gets below -80C! At that temperature, you get rare clouds forming that you don't get anywhere else. The CFCs -the chemicals from man-made products that started the hole in the ozone -deposit double chlorine particles (Cl2) on these clouds. When the sun comes out in spring, it splits these doublets into separate chlorine molecules, which destroys the ozone

Catherine - Why isn't ozone depletion compensated for by other parts of the ozone layer?

Brian - Darkness in winter causes very cold temperatures. This causes a stratospheric vortex of air, which keeps to itself and excludes other parts of the stratosphere. There isn't a chance to get ozone from elsewhere until the vortex breaks down when the sun comes back. The ozone each year heals in the spring, but it never gets back completely.

Chris - Why isn't there a hole in the North Pole?

Brian - Everything that happens in the South Pole should happen in the North Pole, but the vortex is different. In the South Pole you have one big circular continent with the ocean going around it. In the North Pole, you have the continents and oceans next to each other. Because land and sea heat at different rates, the temperatures are more confused. Instead of getting a circular vortex like in the South Pole, you tend to get different shapes and sizes. You start a hole forming but then it gets blown off to the side.

Chris - Have the measures we introduced such as knocking out CFCs made a difference?

Brian - Yes. We have eliminated tough CFCs, and we are adding more chemicals to the list. The amount of those chemicals in the atmosphere is now turning over. The ozone hole that got worse during the1980s has now bottomed out. But we don't expect to see the ozone getting to where it was before until 2070

Human use of Aloe Vera goes back thousands of years and it was named by the Arabs. But how do we actually make preparations from it ?

Rosemary - The plant is like a cactus and the inner gel is used for the products. The leaf is sliced and you scoop out the gel from inside. That can be used to make all sorts of products. You can put it on your skin and you can drink it as a detox. . It's absolutely wonderful for the skin. It has anti-bacterial effects -it just cleans the system out. We get lots of referrals from vets for dogs with skin problems, problems with their immune system and arthritis. It's also used to treat burns in many tropical places.

Chris - What do we know about the history of aloe vera?

Rosemary - It goes back thousands of years -it's written in the history books. Alexander the Great used it, Cleopatra used it for skin cleaning and toning up.

The reason you hear those sounds on TV is to make it more interesting. We know dinosaurs probably made noises because they had very good sense of hearing. If you look at dinosaur fossil skulls, you can trace their ear canals and work out where their ears would have been and the kinds of sound they would have responded to. If they could hear sounds, they could probably make sounds. In the late 90's scientists put a fossil through a CT scanner to look at the bone structure. The headpiece was a series of intricately connected tubes a bit like organ pipes. They analysed the structure of these canals and airways, and used a computer to model what would happen if air were blown past. They found that the dinosaur could probably have produced low pitched rumbling noises that could have carried a long way. So what we use for dinosaur sounds on TV is what can be inferred from studying the shape of their fossilised remains, with a bit of artistic license thrown in.