Will 2020 be the Earth’s hottest year on record?

Climate scientists are poring over global temperature data to determine whether 2020 will surpass 2016 as the planet’s warmest year on record.

The final answer won’t be so clearcut: There are at least six separate data sets for global climate measurements, and each uses a slightly different system for determining our planet’s temperature.

For example, based on measurements through November, it’s likely that NASA’s data will show 2020 as the warmest on record. Other groups, such as the National Oceanic and Atmospheric Administration, will probably show 2020 in second place.

“In most datasets, 2020 will be more or less tied with 2016 – at least within the margin of uncertainty in our global temperature reconstructions,” tweeted Zeke Hausfather, a climate scientist and director of climate and energy at the Breakthrough Institute in California. “That’s remarkable in a sense, given that 2020 is a La Niña year and 2016 was a super El Niño event.”

La Niña, a natural cooling of Pacific Ocean water, tends to lower the global temperature, while El Niño does the opposite.

“The record warmth experienced in 2016 was a result of both the long-term human-driven warming trend of nearly 0.4 degree per decade and a super El Niño event,” Hausfather told USA TODAY.

He said 2016 was around 2.22 degrees Fahrenheit warmer than pre-industrial temperatures based on NASA data. “The second warmest year on record – 2019 – was 2.16 degrees warmer,” he said.

U.K. Met Office scientist Nick Dunstone said that “the variability of the La Niña/El Niño cycle is the secondmost important factor in determining the Earth’s temperature but it is simply dwarfed by the forcing effect of increasing greenhouse gases in the atmosphere.”

The U.K. Met Office is another group that measures global temperatures.

“The difference between the groups is mostly to do with how they fill in the ‘gaps’ in the Arctic,” Hausfather told the Independent. There are gaps in our knowledge of temperatures in remote parts of the Arctic Ocean as a result of there being no weather stations in these locations, the Independent said.

Does it really matter which year is the warmest on record? “Ultimately the media cares about new records a lot more than the climate does,” Hausfather said. “What matters for the climate is the long-term warming trend, where we see clear evidence of human activity changing the climate.”