October 2015 global temperature departures from average (NASA)

It was Earth’s warmest October ever recorded and it wasn’t even close. The record-shattering month was right in step with most of the preceding months in 2015 — which is positioned to easily rank as the warmest year on record.

New data from the Japan Meteorological Agency and NASA show that the planet obliterated October records established just last year.  October 2015 out-baked October 2014 by 0.34 degrees (0.19 Celsius) and 0.32 degrees (0.18 Celsius) in JMA and NASA’s analyses, respectively.


Time series of the global average October temperature (Japanese Meteorological Agency)

And these records are breaking records.

The planet’s temperature departure from the long-term average  of 1.04 Celsius in October is the greatest of any month ever recorded by NASA.  It marked the first time a monthly temperature anomaly exceeded 1 degrees Celsius in records dating back to 1880.  The previous largest anomaly was 0.97 Celsius from January, 2007.

Monthly global temperature departure from average in degrees Celsius (divide by 100 for specific departure).
Monthly global temperature departure from average in degrees Celsius (divide by 100 for specific departure).

The toasty October put another exclamation mark on a year that has essentially locked up the title of warmest on record.

In August, the Earth’s average temperature was running so far ahead of 2014, the previous warmest year, that NOAA said there was 97 percent chance 2015 would surpass it.

Then, the planet recorded its warmest September ever recorded by an unprecedented margin.

[After record-shattering September, 2015 in commanding lead for Earth’s hottest year on record]

Earlier this month, Britain’s weather service, the Met Office, and NASA both stated that the Earth’s average temperature is likely to rise 1 degree Celsius above pre-industrial levels for the first time by the end of this year. This milestone is significant since it marks the halfway point to two degrees Celsius, the internationally accepted limit for avoiding the worst consequences of climate change.

[The world is off course to prevent two degrees C of warming, says energy agency]

Temperatures have trended upward over the last several decades, spurred by increasing and unrelenting emissions of heat-trapping gases like carbon dioxide. Meanwhile, since the spring, a strengthening El Niño event, which is now near record levels, has bumped this year’s temperatures to all-time highs.

[By one measure, this wicked El Niño is the strongest ever recorded: What it means]

El Niño events release vast amounts of heat from the tropical Pacific into the atmosphere. This year’s event is near its peak and may begin to weaken soon, but is expected to remain strong into the winter, likely keeping global average temperatures above or at least very near previous record levels.