What's Up In Climate Change? Earth just racked up its warmest winter on record
Friday, March 20, 2015, 4:46 PM - It may not have felt like it in the eastern half of North America, but take the rest of the world into account too, and this past winter ranked warmer than any other on record.
As the northern hemisphere approaches the official end of winter, experts have tallied the numbers for this past meteorological winter - Dec 1 to Feb 28 - and found that it ranked as the warmest that the Earth has seen since record keeping began, over 135 years ago.
According to NOAA:
Together, the record warm December, second warmest January, and second warmest February made the combined average temperature over global land and ocean surfaces for the December–February period the highest on record for this period, at 0.79oC above the 20th century average of 12.1oC, surpassing the previous record warmth of December–February 2006/07 by 0.04oC. The Northern Hemisphere had its warmest winter on record and the Southern Hemisphere had its fourth warmest summer.
In addition to this past Dec-Feb season coming in as the warmest Dec-Feb on record for the globe, and the warmest winter ever recorded for the northern hemisphere, this northern winter apparently also surpassed the warmest winter ever seen in the southern hemisphere.
According to NOAA records, whereas Dec-Feb 2014/15 in the northern hemisphere came in at 1.03oC above the 20th century average, the warmest southern winter - June-August 1998 - was only 0.65oC above average. The differences in the ratio of land-to-water surface between the hemispheres accounts for some of this variation, as southern hemisphere temperatures don't tend to reach the same extremes above or below average that are seen in the north. However, simply based on what each hemisphere is used to, this northern hemisphere winter appears to rank as the warmest overall.
How could this be the warmest winter on record, when eastern regions of Canada and the United States suffered through frigid temperatures and extreme snowstorms? As the graphics below reveal, the eastern half of North America was one of the very few places on land that were significantly colder than average for the season.
In stark contrast, that cold was flanked by some of the warmest temperatures on the planet for the season.
The western half of North America was significantly warmer than average, with regions all the way up the west coast of the United States and into southwestern British Columbia tagged as having the warmest winter on record.
Meanwhile, temperatures over the Atlantic Ocean, just to the east of the warm Gulf Stream current, also came in as the highest on record. Along with the warmth of the Gulf Stream itself, this pattern of heat very likely helped to fuel the impressive snowstorms that battered the east coast.
Adding to this assessment, NOAA also stated that the Year-to-Date for 2015 is also setting records.
Although, individually, January 2015 and February 2015 have ranked as the 2nd warmest on record (Jan 2007 and Feb 1998 still rank as 1st), the combination of both months together surpassed the previous Jan-Feb Year-to-Date record (a tie between 2002 and 2007) by 0.04oC.
What does this mean for the rest of 2015?
There's still 10 months of records to go through before any definite statements can be made about this year, of course. That's plenty of time for things to cool down.
However, with El Niño now considered to be in full-swing in the equatorial Pacific Ocean, and the warming effect that this weather-ocean pattern has on global temperatures, things are not looking good. One only needs to compare El Niño records with the list of hottest years on record to see that the only years on the list that weren't being strongly influenced by this large-scale weather pattern at the time were 2013 and 2014.
Even though this particular El Niño has developed as an El Niño Mokoki - with the majority of the warm sea surface temperatures in the middle of the ocean, rather than closer to South America - its effects could still push 2015 to surpass 2014 as the hottest year on record.
Update: An earlier version of this story did not include a comparison of this northern winter's temperature anomalies with the temperature anomalies from the warmest southern winter on record.