I figured I would start our look back at 2015’s weather from a world perspective, then zoom into North America, Canada and Western Canada in particular in an upcoming article.
I have to pretty much agree with the top two 2015 global weather stories chosen on nearly every website: 2015 saw earth’s hottest year in recorded history, and the strongest El Niño event in recorded history. Some other weather firsts that occurred during 2015, I think it’s pretty hard to argue against these two events winning out.
In actuality, we probably wouldn’t have had one without the other. I say that because El Niño helps to contribute extra heat energy into the atmosphere, raising global temperatures already running on the high side due to global warming. The warmer global temperatures in turn help to increase already-warm ocean temperatures, leading to an even stronger El Niño event.
Let’s begin by looking at global temperatures in 2015. While we are still waiting for the final numbers to come out of NOAA and NASA, it is pretty much a forgone conclusion that 2015 will beat 2014 as the warmest year since reliable records began in 1880. According to NOAA, for the 11-month period from January to the end of November, Earth’s average temperature was 0.87 C above average. This compares to 0.73 C above average for the same time frame in 2014. While NOAA and NASA have not come in with their December values, the University of Alabama in Huntsville has ranked this December as the third warmest in the satellite data set. Its values are derived from satellite measurements of the lower eight kilometres of the atmosphere and are usually lower than what NOAA and NASA report. What is interesting, or rather, important about the University of Alabama in Huntsville, is that none of the funding for its work comes from oil, coal or industrial companies or from any private or special interest groups. I’ll let you know what the final numbers are for 2015 as soon as they’re out.
Coinciding with the warmest year on record is the record El Niño event beginning to wind down across the Pacific. As we moved into 2015, a weak El Niño event was already developing in the Pacific and forecasters called for a very high chance that this particular El Niño event would become strong, possibly record strong. By July, temperatures in the key El Niño region of the Pacific had warmed enough for it to be classified as a strong event and by November, ocean temperatures peaked at 3.1 C above average, which broke the one-week record of 2.8 C set during the El Niño event in 1997. The final classification for an El Niño event uses a three-month average and this finds 2015’s event tied with that in 1997, with a reading of 2.3 C above average.
While we know that El Niño can bring milder-than-average temperatures to Western Canada during the winter, overall El Niño tends to warm global temperatures by as much as 0.1 C as extra heat from the ocean is transferred into the atmosphere. While El Niño is slowly weakening and is expected to become neutral sometime late this spring or summer, it will continue to dump extra heat into the atmosphere. This, combined with ongoing global warming, will likely result in Earth seeing her third straight warmest year on record in 2016.
Other broken records
The global weather event I’ll list as third for 2015 is really several different weather events that were all similar in nature. They are also partially tied into the record-warm global temperatures and El Niño. What I am talking about are hurricanes. While the Atlantic basin saw a relatively quiet hurricane season, this was not the case around the world.
First of all, the Western Hemisphere saw its most powerful hurricane on record during 2015, when Patricia became a Category 5 storm on Oct. 23 off the coast of Mexico. At its peak, Patricia had sustained winds of 320 km/h and a central pressure of 879 millibars. The northeast Pacific saw a record 11 major hurricanes, which broke the previous mark of 10 set in 1992. The central Pacific was also busy, with 14 named storms, eight hurricanes and five major hurricanes that either formed in this region or tracked into it. This broke all three of the old records which were 10 named storms, five hurricanes and three major hurricanes. Record-high ocean temperatures, along with lower-than-usual wind shear due to the strong El Niño, helped to create an environment that was very conducive to hurricane development. Interestingly, if you check out the composite image of all the tropical cyclone activity across the Pacific, shown here, the region around Hawaii was largely unaffected.
The southern Pacific also saw an active hurricane season (or typhoon, as they’re called in that part of the world). The most interesting was tropical cyclone Pam, which hit Vanuatu as a Category 5 storm with sustained winds in the 265 km/h range. With a central pressure of 896 mb, it was the second-strongest tropical cyclone ever measured in that part of the world. It was also only the 10th time a Category 5 tropical cyclone was recorded in this region.
Next time we’ll hopefully be able to zoom in closer to home and look at the top weather stories from around our part of the world.