PARIS (AFP) - The area covered by Arctic sea ice reached its lowest point this week since the start of satellite observations in 1972, German researchers announced on Saturday. On September 8, the extent of the Arctic sea ice was 4.240 million square kilometres. This is a new historic minimum, said Georg Heygster, head of the Physical Analysis of Remote Sensing Images unit at the University of Bremens Institute of Environmental Physics. The new mark is about half-a-percent under his teams measurements of the previous record, which occurred on September 16, 2007, he said. According to the US National Snow and Ice Data Center (NSIDC), the record set on that date was 4.1 million sq km. The discrepancy, Heygster explained by phone, was due to slightly different data sets and algorithms. But the results are internally consistent in both cases, he said, adding that he expected the NSIDC to come to the same conclusion in the coming days.