The video notes that we have always had flooding which is correct - that is something we have noted as well, like in this presentation to the WEAO / OWWA joint climate change committee: https://www.slideshare.net/RobertMuir3/infrastructure-resiliency-and-adaptation-for-climate-change-and-todays-extremes
The presentation noted how GO Train flooding, Toronto Island flooding and Toronto basement flooding area note new phenomena as shown in these images:
A review of the inquiry for Premier Davis on Toronto Don River flooding noted flooding since the 1800's as noted in this post: https://www.cityfloodmap.com/2015/07/go-train-flooding-not-new-1981-inquiry.html - an Environmental Assessment in 1983 noted this:
This Acres Consulting report noted the influence of hydrologic changes on peak flows and flood damages. We have described these changes as well such as in this JWMM paper: https://www.chijournal.org/C449
GTA watershed urbanization changes were summarized as follows:
Here is a wider perspective:
We have assessed the trends in extreme rainfall which supported the CBC Ombudsman decision - here are the english-version findings: https://www.cityfloodmap.com/2019/06/office-of-ombudsman-french-services.html
Even Minister McKenna has reinforced comments made in Canada's Changing Climate Report stating in a June 2019 letter "the observational record has not yet shown evidence of consistent changes in short-duration precipitation extremes across the country":
Other CBC story corrections about extreme rainfall are summarized here: https://www.cityfloodmap.com/2019/06/cbc-correcting-claims-on-extreme.html
As the Climate Discussion Nexus video notes, the insurance industry has claimed that there is an increase in extreme rainfall caused by climate change - this has been reiterated by senior executives as in this op-ed in the Globe and Mail by Charles Brindamour and Dean Connor "Climate resilience must be part of every government’s agenda" (The Globe and Mail. September 25, 2018. https://www.theglobeandmail.com/business/commentary/article-climate-resilience-must-be-part-of-every-governments-agenda/), or as in this op-ed in the Financial Post by Craig Stewart "Counterpoint: Insurance claim costs are rising because severe weather is making flooding worse" (Financial Post. February 7, 2019. https://business.financialpost.com/opinion/counterpoint-insurance-claim-costs-are-rising-because-severe-weather-is-making-flooding-worse).
Unfortunately, the insurance industry has not ever offered any data on increasing extreme weather trends to counter Minister McKenna's recent statement or the CBC Ombudsman findings since 2015. The insurance industry has in the past mixed up future predicted extreme rain trends with past observations as in the "Telling the Weather Story" report:
As noted in our Financial Post op-ed, the insurance industry has claimed a correlation and causation between extreme weather and flood damages. Unfortunately, there is no rain trend to correlate to making any causation discussion moot. As Dr. Dickinson explains in the video, warmer winters mean lower spring flood potential, and urbanization drives urban flood stresses, not changes in rainfall. More on this University of Guelph analysis is here:
Our rebuttal to the insurance industry's suggested correlation / causation was in the Financial Post: https://business.financialpost.com/opinion/hyped-up-misleading-insurance-myths-about-severe-weather-flooding-distract-us-from-real-problems
Well done John Robson and Climate Discussion Nexus for sharing information on this topic.
More reading? - what do engineering studies in southern Ontario say about extreme rainfall trends? typically no past change - see compiled reports / analysis here: https://www.cityfloodmap.com/2018/03/extreme-rainfall-and-climate-change-in.html