The year 2016 has been adjudged as the warmest year in last 38 years, dislodging 1998 from the hottest year slot. This is based on close to four decades' worth of satellite temperature measurements.

This was revealed by John Christy, the director of the University of Alabama's Earth System Science Center in Huntsville.

According to him, 2016 was warmer by +0.02 degrees Celsius compared to 1998. Even after conceding an error margin to 0.10 degrees Celsius, which means a statistical tie with 1998, Christy said the last year may still qualify as warmest as the Northern Hemisphere was extra hot in 2016.

Based on global average temperatures from 1981-2010, the atmosphere was warmer by +0.484 degrees Celsius in 1998, while it was +0.505 degrees Celsius hotter in 2016.

Given that temperature trends from satellite data are a tad lower than those based on thermometer readings across the globe, other groups may also pronounce 2016 as the warmest year.

El Niño Effect

"The question is, does 2016's record warmth mean anything scientifically?" Christy said. "I suppose the answer is, not really. Both 1998 and 2016 are anomalies, outliers, and in both cases, we have an easily identifiable cause for that anomaly: A powerful El Niño Pacific Ocean warming event."

He said climate studies usually treat phenomena like El Niño as transient, as the focus is on long-term trends as far as temperature is concerned.

2016 Temperatures

The data noted instances of high and low temperatures. The warmest average temperature anomaly in December 2016 was recorded at south central China's Qamdo town, where the average temperatures during the month were 3.91 degrees Celsius hotter than seasonal trends.

As for the the coolest average temperature, a place in Saskatchewan had December temperatures averaging 4.13 degrees Celsius cooler than seasonal norms.

Christy, together with ESSC principal scientist Roy Spencer, was able to obtain precise temperature readings for various regions of the Earth including deserts, oceans, and rain forests through data collected by microwave sounding units on NASA and NOAA satellites.

Meanwhile, the Copernicus Climate Change Service, a wing of the Copernicus earth observation program run by the European Union, also confirmed 2016 as the warmest year on record.

Its figures showed temperatures of 2016 on a global scale crossed 14.8 degrees Celsius and were up by nearly 1.3 degrees Celsius. The C3S also said that 2016 was close to 0.2 degrees Celsius warmer than 2015.

One reason for the global temperatures soaring above average in the second half of 2016 was the disappearing sea ice cover in the Antarctic and Arctic.

Outlook For 2017

Predictions are also out on how 2017 will fare in terms of global temperature. It is expected to be among the hottest years in more than 130 years of record-keeping.

According to the UK Met Office, El Niño might be over, but 2017 will be one of the hottest.

According to forecasters, 2017 temperatures would decline between 0.63 and 0.87 degrees Celsius above the 1961-1990 average. However, "the dip in 2017 is much smaller than the long-term increase," noted Adam Scaife, head of long-range prediction at the Met Office.

And because of the rising temperatures brought about by global warming, "each new year is basically predestined to be among the warmest on record," said Deke Arndt, who heads the climate monitoring division of the U.S. National Centers for Environmental Information.