London Telegraph 
October 28, 2011
Japan’s nuclear disaster in Fukushima released twice as much radioactivity into the atmosphere as the authorities initially estimated, according to a new report.
A worldwide network of sensors found that levels of radioactive caesium 137 released from the damaged nuclear plant were significantly higher than anticipated, according to the Norwegian Institute for Air Research study.
The Japanese government estimated that 15,000 terabecquerels of caesium were released after the plant was damaged, while the new study put the figure at 36,000 terabecquerels – 40 per cent of the total released from Chernobyl.
Andreas Stohl, author of the preliminary study, focused on the emission of caesium 137, a slow decaying element which can last for 30 years in the environment and release cancer-causing radiation.