Key Science Content

After viewing the video and participating in one or more of the Hands-On Activities, students will be able to:
• describe the physical and atmospheric processes which produce the Antarctic ozone hole
• describe research seeking to understand the effects of increased levels of ultraviolet radiation (UV-B) on plants and animals
• explain and discuss how global warming might affect the Antarctic ice sheets and sea level rise around the world
• describe and discuss, by reference to this and the preceding videos, why Antarctica provides a unique scientific research site, and refer to comments from some of the researchers about living and working in Antarctica

Program Description
"We shall not cease from exploration," wrote the poet, T.S Eliot, "and the end of all our exploring will be to arrive where we started, and know the place for the first time. The end is where we start from." In terms of global climate change, the poet was right: the poles turn out to be more sensitive than just about anywhere else on Earth. The ends are where climate change "starts from." This program and associated Hands-On Activities and online resources provide a way to show how changes to ozone on the molecular level can have global consequences, why changes in the ice sheets are so important, and how Antarctica serves as a window to the past, present and future of global weather and climate.

• "The Ozone Hole and UV-B" (05:20) Katy Jensen (she's referred to by her maiden name, McNitt, in some of the previously published Guides and online materials) has now wintered at the Pole some 3 times, making her one of the few humans to have spent so many months of night at the end of the Earth. In this sequence she explains her former work for NOAA where she helped to monitor the Antarctic ozone hole, providing ground truth by regularly launching balloon sondes. NASA satellite images show the hole in recent years. Computer graphics show how the chlorine in CFCs can knock atoms off of ozone, the process which promotes the annual polar ozone hole. Jensen notes that the ozone hole results in increased levels of ultraviolet radiation, or UV-B, which creates skin cancers and potential crop damage. In scenes taped close to NSF's Palmer Station, we see University of Arizona researchers Tad Day and Chris Ruhland running their carefully controlled experiment to assess if and how UV-B affects some of the only "vascular" (having vessels to channel liquid through stems) plants in the Antarctic. Ruhland notes there's conflicting evidence, with some data showing UV-B promoting growth, and some showing harmful effects. More recent studies, however, have shown that increased levels of UV-B do indeed harm phytoplankton, ice fish and other marine organisms. Teachers and students should use the WWW to track each season's ozone hole, and the latest findings about UV-B.

• "Ice and Water" (02:31) As first seen in program 2, one major focus of USAP research is to assess the stability of the Antarctic ice sheets. In this sequence, we see geologist Ted Clark at work in Central West Antarctica, and hear his estimate that melting some or all of the West Antarctic ice sheet could result in a 6 meter (20 feet) rise in sea-level, something that would seriously threaten such major North American cities as Miami, New York, Boston and San Francisco, and totally inundate many small nations in the mid-Pacific. Ross Powell says that this question motivates his underwater research on what's happening at the "grounding line," where glaciers slide into the ocean.

• "Past, Present and Future" (04:00) In the final sequence of this program and the series we see research that typifies much work in the Antarctic: interdisciplinary, international and with clear implications for the entire planet. Paul Berkman from the Byrd Polar Research Institute in Ohio is studying a very humble creature-fossil clams, whose shells are found all round the coasts of the continent. As Berkman explains, cold water results in chemical changes in the shells which make them thin. Warmer waters produce thicker shells. Thus once you've dated the shells, you can begin to plot changes in past Antarctic climate. As we saw in program 2, such climate history can then help inform our awareness of future climate changes. Physics and chemistry shape biology, and understanding the past can help us make sounder policies for the future. We end with comments from 3 of the researchers appearing in this program: their remarks capture the combination of awe at the natural environment, dedication to science, and personal satisfaction it's so easy to find in members of the USAP:

Paul Berkman:
Antarctica is a spectacular region on the planet. Live in a place, or come to a place to visit, that is surrounded by beautiful glaciers, very jagged peaks... even the storms and the way they lash the environment is interesting. I feel very fortunate in being able to come to this place.

Ross Powell:
It's absolutely spectacular. There's no other words for it. With the scenery you have here, and the peace and quiet, and just the environment is just so exhilarating, and then being able to get the scientific results that we are, that's really the icing on the cake.

Katy Jensen:
It's magic.