Last month was the hottest January on record, according to scientists

Last month was the warmest January in 141 years of climate record-keeping, according to a monthly assessment by the National Oceanic and Atmospheric Administration. The January 2020 record beat the January 2016 record by 0.04 degrees Fahrenheit (0.02 of a degree Celsius).

The warmest year ever recorded is 2016, followed by 2019. Both, however, could be displaced if this year's first month marks a trend.

According to a statistical analysis by NOAA's National Centers for Environmental Information scientists, 2020 is "very likely to rank among the five warmest years on record."

Global land and ocean surface temperatures in January 2020 were 2.05 degrees Fahrenheit (1.14 degrees Celsius) above the 20th-century average, according to NOAA. No land or ocean areas had record-cold January temperatures.

Notably, the record was "the highest monthly temperature departure without an El Niño present in the tropical Pacific Ocean." El Niño is a natural cycle of warming of the Central and sometimes Eastern Equatorial Pacific sea surface temperatures, occurring every few years on average.  

Temperatures have been ticking up in the 21st century. The 10 warmest Januaries have all occurred since 2002, with the four warmest all taking place in the last four years. 

The past 10 years marked the warmest decade on record, according to an annual global climate report released in January by NASA and NOAA. The past five years have been the warmest of the last 140 years.

"January 2020 marked the 44th consecutive January and the 421st consecutive month with temperatures, at least nominally, above the 20th-century average," according to NOAA.

While January 2020 was the warmest January so far overall, different parts of the globe saw differences in temperature rankings. The Northern Hemisphere had its warmest January on record, at 2.70 degrees F (1.50 degrees C) above average, but the Southern Hemisphere only had its second-warmest January on record, behind 2016.

According to NOAA, "the most notable warmer-than-average land temperatures" this January "were present across much of Russia and parts of Scandinavia and eastern Canada, where temperatures were 9.0°F (5.0°C) above average or higher." On the opposite end of the spectrum, "notable cool temperatures" were recorded in January across much of Alaska and parts of western Canada, with temperatures 7.2°F (4.0°C) below average or less.

While global temperatures increased in January, the weather in a particular region may not have correlated. This is because one month, or even one year, is not necessarily indicative of climate. 

"The difference between weather and climate is a measure of time," according to NASA. "When we talk about climate change, we talk about changes in long-term averages of daily weather." 

In:
• National Oceanic and Atmospheric Administration
• NASA