Data vs Cartoon Infographics? Ontario Extreme Rainfall Data Trends Show Increases and Decreases, Contradicting Environmental Commissioner of Ontario 2017 Report

ECO Report uses a cartoon call-out to explain climate change trends
in Ontario but fails to provide any data to support statements regarding
historical storm trends. Data tells a different story on storm trends.

The Environmental Commissioner of Ontario (ECO) has released her 2017 Greenhouse Gas Progress Report, Ontario’s Climate Act: From Plan to Progress, to the Ontario Legislature.

The report fails to acknowledge extreme rainfall trends in Ontario, ignoring trends identified by the academic community and fundamental information in the official Engineering Climate Datasets.

Chapter 9 indicates:

"Abstract
Here in Ontario we are already feeling the effects of climate change. Higher average temperatures, more climate extremes and the increased incidence of drought, storms, and unseasonable temperatures are affecting people across the province."

ECO has relied on cartoonish data previously in describing climate change issues, but the ECO infographics contradict engineering data used for infrastructure design and flood risk assessments. Toronto observed annual maximum rainfall trends have been decreasing for durations of 5 minutes to 24 hours.

Unfortunately, local data does not support ECO's stated increased incidence of storms. In fact Engineering Climate Datasets show twice as many statistically significant decreasing annual maximum rainfall trends as increasing ones - these are the observed, measured, documented data trends:

Short duration rainfall in southern Ontario shows many statistically decreases for duration of 2 hours or less and only one statistically significant increase. There are several statistically significant decreases for 5 to 15 minute durations but no increases for the shortest rainfall durations. 

The ECO report exercises an "Availability Bias" to characterize storm incidence stating "  The Toronto floods in 2013, the 2014 floods in Burlington and parts of eastern Ontario, and those experienced on the Toronto Islands, in Windsor, in Cambridge, in Minden and in the Ottawa-Gatineau region in 2017, are all the types of events that climate change makes more likely." Evidence-based policies should instead rely on data to characterize extreme weather risks as opposed to anecdotal lists.

July 8, 2013 was a record rainfall for July 8ths but
daily maximum rainfall has been decreasing.

Despite the fact Toronto experienced a flood in 2013, Toronto rainfall extremes have not increased. The chart at right shows that the 2013 maximum rainfall while above average is still part of a decreasing trend since the 1940's. Media report July 8, 2013 as a record .. which is true for all historical July 8ths - but nobody designs infrastructure for rainfall on particular calendar days. Too often, median and non-technical reports confuse the incidence of flooding with that of extreme rainfall - correlation is not the same as causation when it comes to rain and flooding, as urbanization has significantly increased flooding, despite clear stationary extreme rainfall trends.

Academic research published in the International Journal of Environmental Research, Changes in Rainfall Extremes in Ontario relies on data and peer-reviewed analysis to characterize extreme rain - that rigorous approach indicates no obvious regional pattern:

"Abstract

Many Ontario Extreme Rainfall Trends are decreasing especially in
south west and south east regions.

There is a general consensus that climate change has impact on the intensity and frequency of rainfall events. However, very little research is available about the changes in short term rainfall extremes. The focus of this paper has been on the change in annual and monthly rainfall extremes in Ontario. The results indicate a greater variability (increase and decrease) among stations for shorter durations (15-min, 30-min, and 60-min). There is no obvious regional pattern with possible exception of increasing trends at north-western locations."

The table from the paper below shows that Southwest Ontario and Southeast Ontario rainfall has been decreasing at many climate stations, including many statistically significant decreasing trends. Similar to the Environment and Climate Change Canada's Engineering Climate Datasets, there are more statistically significant deceases than increases.

Extreme rainfall trends in Ontario show decreases and increases.