MIAMI • Humanity's experiment with planetary warming has reached a new level of extremes.

Last month was the hottest February in 137 years of record keeping, according to data released on Thursday by the National Oceanic and Atmospheric Administration. It is the 10th consecutive month to set a new record, and it puts this year on course to set a third straight annual record.

With an average temperature that was 1.21 deg C above the 20th century average, the month marked "the highest departure from average among all 1,646 months in the record".

The latest heat record continues a string of troubling warming trends, which US government scientists say are driven by man-made climate change and the burning of fossil fuels that spew greenhouse gases into the atmosphere.

Last year as a whole was the hottest on record, beating out the previous title holder of 2014. The global average temperature last month was 12.1 deg C, according to NOAA climate scientist Jessica Blunden.

The heat helped prolong the longest planet-wide coral bleaching event. These grim milestones coincide with the biggest recorded jump in carbon dioxide, the most important greenhouse gas.

Unprecedented temperatures in the Arctic melted away layers of ice to record-low levels. Last month, the extent of sea ice in the Arctic averaged 1.16 million sq km, or 7.54 per cent, below the 1981-2010 average. "This was the smallest February extent since records began in 1979 and 77,000 sq miles (199,430 sq km) smaller than the previous record of 2005," said NOAA.

"February 2016 also marked the second consecutive month of record low Arctic sea ice extent."

The heat in the Arctic is especially worrisome, as the region provides a powerful feedback loop for global warming. As the ice melts, it reflects less of the sun's warming rays back into space. The permafrost also serves as a giant repository for carbon, which is released as carbon dioxide and methane as the ice melts.

Melting ice is therefore both a result of current global warming and a trigger for future warming.

While El Nino conditions have peaked, they are still strong and may continue to a lesser extent through June, according to the US Climate Prediction Centre. Then it is pretty much a coin toss whether the Pacific returns to more neutral temperatures or even a cooler La Nina pattern. Either way, the planetary warming trend continues.

BLOOMBERG, AGENCE FRANCE-PRESSE