Last year was officially the Earth's warmest since record-keeping began in the 1880s, the World Meteorological Organization announced Wednesday morning. That means 2016 set a global heat record for the third year in a row according to NOAA and NASA, who held a joint press conference on Wednesday to discuss the record.

Climate scientists say greenhouse gas pollution, which humans are creating primarily by burning fossil fuels and chopping down rainforests, likely contributed to the 2016 record.

"The effect of human activity on our climate is no longer subtle. It's plain as day, as are the impacts - in the form of record floods, droughts, superstorms and wildfires -- that it is having on us and our planet."

"The record is due to a combination of the (natural) strong 2015-2016 El Niño (warming of the tropical Pacific Ocean surface) and the strong global warming trend that has continued from 1970 to the present," James Hansen, former director of the

NASA Goddard Institute for Space Studies, told CNN.

While the warming for the planet was just over 1 degree Celsius, the Arctic continued to warm much faster, with temperatures more than 3 degrees Celsius -- 5.4 degrees F -- above what they were in previous decades.

Though some years will be warmer than others, the overall trend over multiple decades will inevitably be upward as long of concentrations of CO2 in the atmosphere keep increasing.

The UN climate summit in Paris in December confirmed 2C as the danger limit for global warming which should not be passed. But it also agreed to “pursue efforts” to limit warming to 1.5C, a target now looking highly optimistic. /AgroWeb.org