This was interesting to listen to. I guess the tropical rainfalls are causing more fertilizer to runoff into the lakes and cause cyanobacteria blooms which kill our lakes and severely impact our drinking water. I can’t imagine where rainfall is going to end up (monsoons?) if the scientists are correct about temperature warming. Click here to hear the entire interview and the full transcription or read an excerpt below.
Jim Bruce – Well what we’re finding is that both for water quantities and water quality the changing climate which IPCC says is going to continue and get worse is having pretty serious effects, particularly as the atmosphere warms. We get more water vapour or what engineers like to call precipitable water in the atmosphere by 7% per every degree Celsius of warming and this means not that were getting more rainfall but that whenever the atmosphere gets organized to rain it rains more heavily so it doesn’t just rain, It pours and this means we’re getting more surface runoff events in the summer and in the off snow melt season.
Bob Brouse – When you talk about the hard precipitation these are what we all see on the lead on the news. These are these fierce storms that we’re speaking of. Is that the case?
Jim Bruce – Yes indeed and it is resulting in things like the big Toronto flood last year and the big flood in Calgary in June of last year.
Bob Brouse – And according to you this is because there is more water vapour in the air that wasn’t there before? What was the case before? I don’t even know how to put this. What was the case before?
Jim Bruce – Well, as I say, as the atmosphere warms it is able to hold more water vapour. It holds more water vapour to the tune of 7% for every 1 degree Celsius of warming.
Bob Brouse – Wow. So if the atmosphere gets 1 degree warmer globally it could hold 7% more water than it used to. That is what you are saying?
Jim Bruce – Yes.
Bob Brouse – That is amazing Jim. So the practical reality of this to cities around the world, I guess, is they have to deal and cope with more extreme weather. Besides that, is this more or less predictable? Like for instance, I know Milwaukee has been doing tremendous rainwater mitigation, trying to trap it and get it off the wastewater systems. Is this what you’re seeing around the world?
Jim Bruce – We’re not seeing as much good work as we are seeing in Milwaukee and a few other places but there needs to be a great deal of effort. I should say when we get those runoff events with the heavy rains, the runoff picks up lots of phosphorous and other contaminants from agricultural areas and also from cities and urban areas so when we look at the Great Lakes, Lake Erie is seriously back-sliding back in its eutrophic state and that’s because it’s getting more polluted runoff in these heavy rain events and there is apparently more phosphorous on the land and on the urban areas that gets into the runoff and into the lakes and is destroying the improvement that was made in Lake Erie back in the 1990s and early 2000s.