The search engine boss who wants to help us all plant trees

This week we speak to Christian Kroll, the founder and chief executive of internet search engine Ecosia. Christian Kroll wants nothing less than to change the world. "I want to make the world a greener, better place," he says. "I also want to prove that there is a more ethical alternative to the kind of greedy capitalism that is coming close to destroying the planet." The 35-year-old German is the boss of search engine Ecosia, which has an unusual but very environmentally friendly business model - it gives away most of its profits to enable trees to be planted around the world. Founded by Christian in 2009, Ecosia makes its money in the same way as Google - from advertising revenues.