2015 Officially the Hottest Year on Record

The final tally is in: 2015 was the hottest year in recorded history--by a record-breaking margin.

On Wednesday, NASA and the National Oceanic and Atmospheric Administration (NOAA) announced the official record for last year's runaway temperatures, which by NOAA's calculation hit an average of 58.62 degrees Fahrenheit (14.79 degrees Celsius).

That's 1.62 (F) degrees hotter than any average year in the 20th century.

And according to NASA, which measures differently, temperatures in 2015 jumped .23 (F) degrees just from the previous year.

"It's getting to the point where breaking record is the norm," Texas Tech climate scientist Katharine Hayhoe told theAssociated Press. "It's almost unusual when we're not breaking a record."

Scientists say the skyrocketing temperatures, which have unleashed climate change, are also fueled by extreme weather events like El Nino.

"Records will happen during El Nino years due to the extra warming boost they provide," Dr. Michael Mann, a professor of atmospheric science at Pennsylvania State University, told the AP. "That boost of warmth however sits upon the ramp of global warming."

It also means that global populations under 38 years old have lived their entire lives in higher-than-average temperatures, according to the Union of Concerned Scientists (UCS), a scientific advisory organization. The group also said Wednesday's report underscored the need for prioritizing global policies that address climate change and prioritize renewable energy.

"The announcement doesn't come as a surprise, as month after month records were being broken all around the world," said UCS climate scientist Astrid Caldas. "It's significant that 2015 was hotter than the previous record by so much in both [NOAA and NASA's] calculations because it points to a strong warming trend that's been observed lately."

"This trend needs to be reversed if we're to keep global warming below 2degC, the goal of the international climate agreement struck in Paris and the number that scientists believe will avoid irreversible changes to Earth's systems," Caldas said. "This new record highlights how critical it was to get an agreement in Paris and the importance of countries not only following through on their commitments, but going further.

"A massive ramp-up of renewable- and low-carbon- energy will be essential to stay within 2degC of warming and avoid new records being set," Caldas said.