The year 2014 was the world’s warmest on record, despite relatively cool temperatures across parts of North America, two federal agencies responsible for monitoring global climate trends said Friday.

Climate experts from the National Aeronautics and Space Administration and the National Oceanic and Atmospheric Administration, working independently, calculated that the globally averaged temperature over land and ocean surfaces for 2014 was 58.24 degrees Fahrenheit, 1.24°F (0.69°C) above the 20th century average, the highest among all years since record keeping began in 1880. By their reckoning, nine of the 10 warmest years now on record all occurred during the 21st century.

Their finding confirms an analysis by the Japan Meteorological Agency, which announced earlier this month that 2014 was the hottest year world-wide on record. The records used by Japan go back to 1891.

Many scientists attribute the warming temperatures to rising concentrations of carbon dioxide, soot and other greenhouse gases in the atmosphere, such as methane and nitrous oxide, and to land-use changes. Some skeptics, however, have suggested that the rise in global temperatures has actually slowed since 1998, which was itself a record-warm year.

“Why do we think this is going on? The attribution of these long-term trends is a complicated fingerprinting exercise,” but greenhouse gas emissions play a major role, said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies in New York, who helped prepare the analysis.