Global temperatures measured so far this year indicate 2017 is "very likely" to be the third warmest on record, according to the World Meteorological Organization (WMO).
If so, that means 2015, 2016, and 2017 would mark the three warmest years since 1880, according to the WMO, an agency of the United Nations. Last year set the record.
The data were released on the opening day of the U.N.'s climate change conference in Bonn, Germany. Local temperature data were not included in the report.
The scientists say the exceptional warmth of 2016 and 2015 were influenced by some of the strongest El Niño years on record. El Niños — marked by a warming of the Pacific Ocean — tend to increase temperatures worldwide.
The group took note that 2017 has ranked among the warmest years even without an El Niño present. That would make 2017 the warmest year recorded if El Niños were excluded.
The average global temperature from January to September 2017 was approximately 1.1 degrees Celsius above the pre-industrial era, which is dated back to about the year 1750.
"The world also continues to see rising sea levels, with some level of acceleration and increasing concentrations of greenhouse gases," a summary of the report states. "The overall risk of heat-related illness or death has climbed steadily since 1980, with around 30 percent of the world's population now living in climatic conditions with extreme hot temperatures persisting several days a year."
The same group also recently reported that the concentration of carbon dioxide in the atmosphere has surged to its highest level in 800,000 years.