Australia's Ancient Animals: Death of the Megabeasts - Documentary HD

Did climate change kill ancient Australia’s mega-beasts? For most of the Ice Age that characterized our planet for the last 2 million years or so Australia and New Guinea together formed a single landmass, Sahul, where around 90 species of giant animal roamed the land. Today, these leviathans, known as megafauna, no longer exist. What caused their extinction? This question has caused heated debate since the 19th century. Now, is mounting evidence shifting the focus from human responsibility to climate change? Dr Stephen Wroe of the University of New South Wales, puts the case for climate change’s responsibility in this week’s edition of the journal PNAS. Dr Kira Westaway of Macquarie University is an interested and involved researcher who has been following the debate. She and BBC Science Correspondent Jonathan Amos give further context to the argument. Major African food crop, cassava, under threat. There is growing concern over viral decimation of cassava, a crop that feeds 300 million African people. The dual “pandemic” of cassava mosaic virus and cassava brown streak disease is spreading across East-Central Africa. This week, scientists from around the world are meeting to ‘wage war’ against these viruses. Dr James Legg, a Tanzania-based expert from the Consultative Group on International Agricultural Research, outlines some possible plans of attack. Lunar water origin. Water inside Earth and the moon may have a common origin. Dr Alberto Saal at Brown University led a team who examined rocks from the Apollo 15 and Apollo 17 missions, including the famous “orange soil”. Within these small pieces of rock exist remnants of water from the time of the Moon’s formation. Analysis of this water’s composition has revealed that it is very similar to water found in rocks on Earth raising further questions about the giant impact theory of the moon’s formation.