The Bond Fire, triggered by a structural fire that spread into nearby vegetation in Silverado, CA on Thursday, December 3, 2020. Dangerous fire conditions prevail in large parts of Southern California as dry, gusty winds are expected in Santa Ana from the northeast.

Kent Nishimura | Los Angeles Times | Getty Images

2020 is linked to 2016 as the hottest year on record, marking the end of the hottest decade on the books as the world grapples with global climate change, according to a study published on Friday.

The outcome of the Copernicus Climate Change Service, an intergovernmental agency that supports European climate policy, continues an unstoppable upward trend in global temperatures as greenhouse gas emissions store heat in the atmosphere.

“2020 will be characterized by exceptional warmth in the Arctic and a record number of tropical storms in the North Atlantic,” said Carlo Buontempo, director of the Copernicus service.

“It is no surprise that the last decade has been the warmest ever, and it is yet another reminder of the urgency of ambitious emissions reductions to prevent adverse climate impacts in the future,” he said.

Signs of record heat in 2020 increased over the course of the year: dry and hot conditions led to massive record fires in Australia and later in the western United States. The Arctic sea ice fell to the second lowest level ever. and monthly temperature records were destroyed worldwide.

Last year was 0.6 degrees Celsius (1.08 degrees Fahrenheit) above the average for the period between 1981 and 2010 and about 1.25 degrees Celsius (2.25 degrees Fahrenheit) above the average for the pre-industrial period between 1850 and 1850 1900, according to the agency.

Some parts of the world heated up more than others as carbon emissions continued to rise. Europe had the hottest year ever, with temperatures 1.4 degrees Celsius (2.53 degrees Fahrenheit) hotter than 2019, which was previously the warmest year.

The Arctic and northern Siberia recorded the largest temperature increases, reaching over 6 degrees Celsius (10.8 degrees Fahrenheit) above the annual average. Western Siberia had exceptionally hot winter and spring, while the Siberian Arctic and much of the Arctic Ocean had exceptionally hot temperatures in summer and autumn.

Large forest fires near the Arctic Circle also released record levels of carbon emissions in 2020, and Arctic sea ice hit record lows in July and October.

“Until global net emissions go down to zero, CO2 will continue to accumulate in the atmosphere and further drive climate change,” said Vincent-Henri Peuch, director of the Copernicus Atmosphere Monitoring Service.

2016, the hottest year of the previous year, was very hot as temperatures were affected by an El Nino, which sent a significant amount of heat from the Pacific into the atmosphere. The past six years have been the warmest six in history.

– Graphics by Nate Rattner of CNBC