The world's leading scientists agree our planet is in crisis. The last five years have been the hottest on record. Sea levels are the highest in human history. A million species are on the brink of extinction. But world leaders have, for another year, failed to resolve some of the sticking points over how to keep our planet cool, instead postponing those negotiations until next year. That is despite talks in Madrid dragging on for an extra two days. We bring you a Planet SOS special from COP25 in Madrid where Nick Clark takes us through some of the big issues on the table including the call for new, more ambitious emission-reduction targets, climate funding and how to protect the world's most vulnerable people in the face of a climate emergency. From Australia where wildfires continue to burn, to the heart of southern Africa where the once-mighty Victoria Falls have slowed to a trickle, our correspondents unpack the unforgiving nature of climate change. We meet those who choose not to fly and calculate the carbon footprint on the complicated route from London to Madrid. And our science editor Mereana Hond explains the connection between human activities and the crisis affecting our planet. In the end, countries managed to agree on motions calling for greater ambition to cut greenhouse gases in order to limit global warming to 1.5 degrees Celsius. But they pushed difficult issues like the rules on global carbon markets until the next COP, to be held in Glasgow in 2020. A handful of countries including the US, China and Brazil are being blamed. We finish Planet SOS with voices from around the world calling for climate action to protect our planet for future generations. - Subscribe to our channel: http://aje.io/AJSubscribe - Follow us on Twitter: https://twitter.com/AJEnglish - Find us on Facebook: https://www.facebook.com/aljazeera - Check our website: https://www.aljazeera.com/