International day of demonstrations on climate change

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From seabeds to mountaintops, people around the world were staging a day of demonstrations Saturday to call for urgent action on climate change.

The number of 350 ppm originally came from a NASA research team headed by American climate scientist James Hansen, which surveyed both real-time climate observations and emerging paleo-climatic data in January 2008, according to 350.org. It concluded that atmosphere containing carbon dioxide above 350 ppm couldn’t support life on earth as we know it, the group said. “It’s a very tough number,” McKibben said. “We’re already well past it — the atmosphere holds 390 ppm today, which is why the Arctic is melting and the ocean steadily acidifying. To get back to the safe level we need a very rapid halt to the use of coal, gas and oil so that forests and oceans can absorb some of that carbon.” McKibben and Hansen are “messengers” for 350.org, along with prominent leaders and climate change campaigners including Archbishop Desmond Tutu, Bianca Jagger and David Suzuki. “I believe climate change is the 21st century’s greatest human rights and security challenge,” said Maldives President Mohammed Nasheed, who is one of the messengers. His country, an archipelago of 1,200 islands, is threatened with disappearing under water if sea levels continue to rise. “If we cannot save 350,000 Maldivians from rising seas today, we cannot save the millions in New York, London, or Mumbai tomorrow,” he said in a recorded statement released by 350.org. “Climate change is happening, and it is happening faster and with greater severity than previously thought.”