2014 was hottest year recorded on Earth: U.S. climate analyses

Separate studies by NASA the National Oceanic and Atmospheric Administration showed that with the exception of 1998, 10 of the warmest years on record have occurred since 2000.

The reports come at the start of a year when representatives of about 200 governments will meet in Paris to try to agree on a deal to limit global warming to avoid floods, droughts, heatwaves and rising sea levels blamed on increasing emissions of greenhouse gases, which result from burning of fossil fuels such as coal and oil.

"Taken together, the warm temperatures of the recent decades demonstrate the impact of greenhouse gases on our climate, and invalidate the sound bite that global warming has somehow 'stopped,'" said Joe Casola, a staff scientist at the Center for Climate and Energy Solutions.

Since 1880, when record-keeping began, Earth?s average surface temperature has warmed by about 1.4 degrees Fahrenheit (0.8 degrees Celsius), a trend that is largely driven by the increase in carbon dioxide and other human emissions into the planet?s atmosphere, NASA said.

"While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases," Gavin Schmidt, director of NASA?s Goddard Institute of Space Studies in New York, said in a statement.

(Reporting by Irene Klotz and Scott Malone; Editing by Alden Bentley)