The World Meteorological Organization (WMO), a United Nations agency, says that 2015 is the hottest year on record and that 15 of the 16 hottest years on record have been this century.
What an alarming statement. Yet it is contrary to personal experience growing up and living most of my life in southwestern Manitoba. So I reviewed the temperature record for the Brandon CDA weather station covering the period 1890 through 2010 and Brandon A station for the 2011 to 2015 period. This article summarizes data that may be of interest to anyone developing their own perspective on the temperature aspect of the anthropogenic global warming hypothesis.
So how applicable is the WMO statement to Brandon’s situation? The average temperature of the last 15 years was indeed higher than the average of the past 125 years although lower than the 1980s. The average for Brandon in 2015 was 3.5 C. The warmest year on record was 5.7 C in 1987, the next warmest was 4.8 C in 1931. Four of the warmest 16 years from 1890 through 2015 have occurred in the last 15 years.
However, there are problems inherent in this aggregate of daily temperatures that render it meaningless when applied to a specific area.
For example, Brandon’s average daily maximum temperature for July 1936 was 32.3 C and July 11 set the record of 43.3 C. Environment Canada calls it the deadliest heat wave in Canadian history when “the heat was so intense that steel rail lines and bridge girders twisted, sidewalks buckled, crops wilted and fruit baked on trees.”
Surprisingly the average temperature for 1936 was the lowest of any year in the 1930s at 0.7 C. Low temperatures in January, February, March, April and October offset record July heat to put 1936 among the 19 coolest years from 1890 through 2015. Two of those 19 were 2013 and 2014.
I have nevertheless included yearly temperature in the accompanying table to enable comparison with the WMO statement. But I think it is more meaningful to focus on temperatures for June, July and August and on winter extremes. The table shows average temperatures during the entire 125-year period and for the 85 years from 1930 through 2015 to focus attention on the 1930s appearing to have been a turning point for most temperature measures.
- The yearly mean temperature for the period 2000 to 2015 was 0.5 C warmer than the 1890 to 2015 average and 0.2 C warmer than the 1930 to 2015 average.
- The mean June, July, August temperature for 2000 to 2015 was the same as the 1890 to 2015 average and 0.3 C cooler than the 1930 to 2015 average.
- The mean maximum June, July, August temperature for 2000 to 2015 was 0.4 C cooler than 1890 to 2015 average and 0.6 C cooler than the 1930 to 2015 average.
- The mean minimum June, July, August temperature for 2000 to 2015 was 0.6 C warmer than 1890 to 2015 average and 0.1 C warmer than the 1930 to 2015 average.
- The yearly extreme maximum temperature for 2000 to 2015 was 2.3 C cooler than the average for both the 1890 to 2015 and 1930 to 2015 period.
- The yearly extreme minimum temperature for 2000 to 2015 was 2.1 C warmer than the average for the 1890 to 2015 period and 1.4 C warmer than the 1930 to 2015 period.
- The record maximum for 2000 to 2015 was 0.7 C cooler than the average for the 1890 to 2015 period and 0.3 C cooler than the average for the 1930 to 2015 period.
- The record minimum for 2000 to 2015 was 1.5 C warmer than the average for the 1890 to 2015 period and 0.7 C warmer than the average for the 1930 to 2015 period.
In summary, temperatures in Brandon have moderated since 1890. Aside from the yearly average, which as pointed out earlier can be extremely misleading on a local scale, the most noticeable changes are that extreme lows are not as low and extreme highs are not as high as in earlier decades. The alarming statement by the WMO cited above has little or no relevance to what has been experienced in southwestern Manitoba from 1890 through 2015.
I remain skeptical about the hypothesis of catastrophic anthropogenic global warming. When advocates of the hypothesis make statements to the effect that there is evidence of dangerous climate change happening in Manitoba my response will continue to be: show me the facts.
Brian Ransom is a former Manitoba minister of finance