"The Science at the Edge" series takes a look at the latest developments and theories that are always intriguing, but may give rise to controversy and concern. It highlights science that is relevant to the lives of many people, and includes provocative discussion themes. Make up your own mind about these cutting edge topics. "Global Warming" looks at the causes of temperature change and its profound effect for life on Earth. It shows how historical clues, such as ice cores, are evidence that temperature fluctuation is not a new phenomenon, and how the causes of our current changing climate are a result of human activity. Learn about dramatic heatwaves, coral bleaching, El Nino events, and how methane and CFCs affect the atmosphere. Consider the uses of renewable and alternative energy sources, from powering cars and homes with photovoltaic cells, to erecting vast wind farms and nuclear power stations.