According to data released on Monday by NASA's Goddard Institute for Space Studies, this past month was the warmest September in the 136 years since record-keeping began for this kind of data. According to the 2014 National Climate Assessment, a report compiled by a team of more than 300 experts, temperatures have increased at the Earth's surface, in the atmosphere and in the oceans over recent decades, while snow and ice cover have decreased. Sea levels are rising, season lengths are changing and "increasing trends in extremes of heat and heavy precipitation events" have been been observed globally, according to the NCA's report. The string of temperature records brings global warming close to the 2°C (3.6°F) level of warming that scientists warn could lead to the worst effects of climate change. In February, the global temperatures were 1.2°C (2.2°F) higher than average.The Nasa figures are calculated using publicly available information from about 6,300 weather stations around the world, including ships and buoys that measure the temperature of the sea.