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...

As our planet warms and poor water and land use practices contaminate our waterways and damage the environment, global water supplies are being affected. Planet SOS looks at what is being done to protect this vital resource. Al Jazeera's Nick Clark travels to Kenya's Mara River Basin. It is home...