Right now, the government of Russia is holding in custody the Arctic Sunrise, a ship crewed by 30 environmental activists from the organization Greenpeace International. They attempted to board a Russian offshore oil platform, demonstrating against drilling for fossil fuels in the fragile environment of the Arctic. Their protest, which may lead to charges of piracy, comes at the same time as news that not so long from now - by mid-century or even sooner - summer in the Arctic Ocean will be ice free. Since 1980, thanks to global warming, the Arctic already has lost around forty percent of its sea ice cover, and that is having a huge effect on climate and the way the wheels and gears of the Earth are supposed to work. According to Greenpeace International Executive Director Kumi Naidoo, "Greenpeace activists and other environmental and social activists standing up for a more just, equitable and sustainable world are putting their lives on the line on a regular basis. What is at stake is humanity's ability to live in coexistence with nature for centuries to come." Naidoo dared to scale an oil rig in the Artic only to be hammered with freezing water from a high-powered hose aimed right at him. The charismatic leader of Greenpeace International saved himself by thinking about his daughter, who inspired his activism in the first place. Naidoo was held for four days in a Greenland jail after one of these perilous climbs but it was not the first time he's seen the inside of a cell. From his teenage years in South Africa, he was a vocal and powerful opponent of apartheid, incarcerated and beaten so often he finally fled to Britain, where he was awarded a Rhodes scholarship to Oxford. When apartheid ended, Naidoo went back to South Africa and became a prominent human rights activist with a growing concern for the impact of climate change on impoverished people of color. In 2009, he brought his negotiating and advocacy skills to the leadership of Greenpeace International, now a worldwide organization of three million members. Naidoo joins Moyers & Company (check local listings) this week to discuss the politics of global warming and the urgency of environmental activism.