River Thames pollution, Arctic freshwater bulge - Planet Earth Podcast - 12.03.05

This week in the Planet Earth Podcast, Sue Nelson goes to the River Thames in central London to find out why nitrate pollution has trebled since the 1930s. Later on, she talks to a researcher about an unusual freshwater bulge in the Arctic, and asks if we should be concerned. Finally, we hear a round-up of some of the news from the natural world.