2015 was warmest year since records began in 1880

Fueled by a combination of the natural El Niño climate pattern and man-made global warming, 2015 was the planet's warmest year since records began in 1880, federal scientists announced Wednesday.

The average temperature across the Earth's land and ocean surfaces was 1.62 degrees above average in 2015, according to the National Oceanic and Atmospheric Administration (NOAA). It was largest margin by which an annual global temperature record has ever been broken, NOAA said.

The global average temperature in 2015 was 58.62 degrees, breaking the record set last year by about a third of a degree, according to NOAA's data. Although these numbers sound small, they're quite large in climate science, where records are often broken by tenths or even hundredths of degrees.

A separate analysis of data from NASA concurred with NOAA's findings. Most of the warming has happened in the past 35 years, and 15 of the 16 warmest years have occurred since 2001, NASA said.

“2015 was remarkable even in the context of the larger, long-term warming trend,” said Gavin Schmidt, director of NASA's Goddard Institute for Space Studies. And 2016 is likely to be even warmer than 2015, he added.

Regardless of El Nino, the long-term warming trend over the past few decades can be linked to the burning of fossil fuels that are releasing gases such as carbon dioxide, he said. The burning of the oil, gas and coal for energy releases "greenhouse" gases such as carbon dioxide and methane. These gases have caused the Earth's temperature to rise over the past century to levels that cannot be explained by natural variability.

For the first time on record, the planet is 1 degree Celsius (1.8 degrees Fahrenheit) warmer than during pre-industrial times, NOAA and NASA said.

That’s an important milestone as world leaders have set a threshold to avoid warming of 1.5 or more degrees Celsius. "We don’t have very far to go to reach 1.5 degrees,” said Thomas Karl, director of NOAA's National Centers for Environmental Information in Asheville, N.C.

Some of the warmest temperatures occurred in portions of central and South America, Europe and central Asia, NOAA reported.

Measurements of carbon dioxide (CO2), the gas most responsible for global warming, continued to set new monthly records in 2015 — for the first time on record, routinely above 400 parts per million (ppm), NASA said. The last time carbon dioxide reached 400 ppm was roughly 4.5 million of years ago, according to a 2009 report in the journal Nature Geoscience.

The rising heat was accompanied by extreme weather events such as heat waves in India and Pakistan that killed thousands; continuing drought and record-low snowpack in California; crop failures raking large parts of Africa; uncontrolled wildfires in Indonesia; and record rains and flooding in Texas, Oklahoma and other U.S. states.