How did Canada fare during Earth's hottest summer on record?
Thursday, September 17, 2015, 5:35 PM - The numbers have been tallied and the combination of June, July and August of 2015 is now officially the hottest northern summer ever for the globe, in 136 years of weather records. How did Canada fare during this milestone season?
Warmest August and hottest Summer on record
Gathering data from around the globe, NOAA now ranks August 2015 as the hottest month of August in 136 years of weather records, at 0.85oC above the 20th century average. This beats out August 2014 by more than a tenth of a degree Celsius (0.11oC).
In addition, since June and July from this year already ranked as the hottest of those respective months (at +0.88oC and +0.81oC compared to the 20th century average, respectively), adding August's +0.85oC to the record also pushed Summer 2015 to the top of the list as hottest on record*.
Credit: NASA GISS
How did Canada fare during this sultry season for the planet?
Even as several other parts of the planet - specifically in South America, Africa, southwestern Europe, and across three major oceans - experienced record high temperatures, and much of the planet experienced temperatures at least "much warmer than average," regions of Canada represented one of the real anomalies with regards to these record-setting temperatures.
As shown in the composite map to the right, showing June, July and August monthly average temperatures for Canada:
Western Canada - specifically B.C. and Alberta - joined the trend of the rest of the world, with above average temperatures to start, shifting towards average temperatures later in the season.
Eastern Canada went through a very cool summer for the most part, ending off with a more seasonable to warm August.C
Central Canada, especially the Great Lakes region, saw a very cool summer overall, at least a degree or two below average. That doesn't equate to record setting cold, however it certainly bucked the trend that the rest of the world is setting.
Why was central Canada so cool compared to the rest of the country, and the world? The large swath of cooler-than-normal temperatures across the North Atlantic, largely attributed to the cold, fresh water flowing off melting Greenland glaciers, is very likely a big culprit in creating this anomaly.
How likely is it now that 2015 will be the new warmest year on record?
According to NOAA and ERT, Inc scientists, in order to figure this out, they use a three-step methodology:
Account for the long-term warming signal
Describe how widely monthly temperatures have fluctuated in the past
Describe thousands of plausible August-December temperature outcomes
"Following this three-step approach, we estimate a 97% probability that 2015 will become the warmest year on record," they wrote in a Sept 17 blog post on Climate.gov.
How, exactly, does this year compare to other hottest years on record?
Based on the graph below - which plots the five previous hottest years, as well as 2013 for comparison - while the other years saw monthly records that hovered around the same levels, the record so far in 2015 is leaving very little doubt.
That's technically not enough to call it, however. Examining the possible outcomes of the rest of the year is necessary to get a solid idea of exactly how likely this really is, and the scientists have been very thorough in their analysis:
In fact, not only will 2015 - in all likelihood - become the hottest year on record, this may represent the latest "step up" in the global temperature record we've seen over the past 45 years.
*Note: June-July-August was summer only for the northern hemisphere. However, the Dec-Jan-Feb period of 2014/2015 - the last, and warmest, southern summer for the globe - was only +0.79oC compared to the 20th century average. Thus, even when taking hemispheres into consideration, June-July-August 2015 was still the warmest summer on record for the globe.