The record-breaking year continues a long-term warming trend - 15 of the 16 warmest years on record have now occurred since 2001.

Temperature analyses released today by the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) reveal the Earth's temperature rose 0.23 degrees Fahrenheit in 2015.

The year shattered earlier temperature records set in 2014 by the highest margin ever, raising concerns about the acceleration in climate change.

In addition, the clear reason behind the increase of 1.8 degrees Fahrenheit since the late 19th century is mainly "increased carbon dioxide and other human-made emissions into the atmosphere", NASA said.

"2015 was remarkable even in the context of the ongoing El Niño", said Gavin Schmidt, director of the NASA Goddard Institute for Space Studies, in the statement.

This illustration obtained from NASA yesterday shows that 2015 was the warmest year since modern record-keeping began in 1880.

In December, world leaders met in Paris to discuss climate change at the 2015 United Nations Climate Change Conference and signed an agreement meant to prevent the globe's average temperatures from rising another 2 degrees Celsius (3.6 degrees Fahrenheit).

This marks "the fourth time a global temperature record has been set this century", the report said.

"People were thinking it was a global warming hoax when the world announced the warmest winter on record - because we were going through one of the coldest in Ontario, Quebec and Atlantic Canada", said Phillips. In addition the temperature increases applied to both land and sea. Since then, nine of the 10 warmest years on record have occurred since 2002, according to NOAA.

Regions of eastern and southern Africa experienced more scorching days than ever, as did large parts of the northeastern and equatorial Pacific boosted by the El Nino weather phenomenon.

2016 is forecasted to be warmer than 2015 as the effects of the El Nino could drive the temperatures upward. NOAA put the number at above 99 percent - or "virtually certain", said Tom Karl, director of NOAA's National Centers for Environmental Information. "Now we don't expect it to last, but it will add to the global warming picture", said Herbert.