Monday, 24 June 2013

Calgary Flooding Podcast Transcript

Hi folks,

I had just finished a facebook status on India's recent 60-year flooding event (just a fortnight or so after Central Europe's multi-century flooding event) when I discovered that 70,000 had been evacuated from Calgary because of yet another flooding event. 

Most media reports (but not this one) are bending over backwards to play down the the connection, but there's an awful lot of 'freak' weather, going on these days. Bob Stanford's interview on Anna Maria Tremonti's podcast about Calgary's flooding just a few days ago was a superb description of the state of play of the current state of  climate science and extreme weather events.

It's so informative, I thought I should provide a transcript.

Anna Maria Tremonti: 'Well Bob Sanford lives in Canmore too, but he's in Winnipeg this morning. He's been trying to make sense of these and other severe floods and he's come to a disturbing conclusion. Bob Sanford is the chair of the Canadian Partnership Initiative of the United Nations Water For Life Decade and the author of "Cold Matters - The State and Fate of Canada's Fresh Waters." ' Good Morning!"

Bob Sanford: " Good morning Anna."

Anna: "Well, what do you make of what we're seeing across Southern Alberta this morning?"

Bob Sanford: "Well, to scientists working in the domain of climate effects on water this is, really the worst of all possible outcomes. We built on flood plains because we thought we had relatively stable climate, the climate that we've experienced over the past century. We thought it would stay the same. We also thought that we had a good grasp of how variable we could expect climatic conditions to be based on what we've experienced in the past century.

And now we've discovered that neither assumption was correct. We do not have adequate means to protect development on flood plains; climatic conditions are more variable than we thought and that variability is increasing as climate changes and we've also discovered that our hydrologic conditions are changing."

Anna: "So what do floods like this tell us about what's happening with our water cycles?"

Bob Sanford: "Well if we put all of the data together they tell us that warming temperatures are altering the form that water takes and where it goes in the hydrosphere. Evidence that increasing temperatures are accelerating the manner and rate at which water is moving through the hydrological cycle is now widely enough available to allow us to connect the dots with respect to what's happening in Canada. So let's start very briefly in the Canadian Arctic. In the North and throughout much of the Canadian Boreal, water that's been trapped as ice in the form of glaciers and as permanent snow pack and permafrost is, is in decline. And the same sort of thing is visibly evident in Canada's Western mountains. There's now evidence that we've lost as many as 300 glaciers in the Canadian Rockies alone between 1920 and 2005. And the same thing that's causing our glaciers to disappear is (in combination with landscape change) changing precipitation patterns on the great plains.

And the same warming is causing water left on the land after the last glaciation in the great lakes region to evaporate. So, you might well ask 'where's all this water going?'  And one of the places it's going is into the atmosphere where it becomes available to fuel more frequent and intense extreme weather events such as the one that you had in Toronto in 2005 that cause $700m [Canadian] worth of flood damage to infrastructure, roads and homes. And you may remember that, in that year, that Calgary just dodged the same kind of bullet - well - not this time. And what we're seeing here is that rising temperatures and the increasing concentration of atmospheric vapour are making what were once predictable, natural events, much worse and what we've discovered is that the atmosphere holds about 7% more water vapour for each degree celsius temperature increase.

And what this tells us is that the old math and the old methods of flood prediction and protection won't work any more. And until we find a new way of substantiating appropriate action in the absence of this hydrologic stability, flood risks are going to be increasingly difficult to predict or to price, not just in Calgary or Canmore, but everywhere."

Anna: " So you're saying, then that there's more condensation in the air. Warm air can hang on to water longer and then - burst when it hits somewhere that can no longer hang on to it?"

Bob Sanford: "Well, warmer atmosphere is more turbulent and it carries more water vapour. And we're seeing that happening widely. We're also seeing in North America disruption in the Jet Stream which is allowing climatic events to cluster and remain in places for longer periods of time, resulting in more intensive floods and droughts. And we're seeing this as a result of the general warming in the atmosphere."

Anna: "And you've said that this is because of Climate Change. How do we know that this isn't just a fluke, an outlier?"

Bob Sanford: "Well, we know that Classius Clapeyron relation is one of the standard logarithms, or algorithms that we use in Climate Science. And we know that as the temperature increases we know what we can expect in terms of water vapour increases in the atmosphere and we're beginning to see some very interesting phenomenon associated with this. Things like atmospheric rivers. Great courses of water vapour aloft that can carry between 7 and 15 times the daily flow of the Mississippi and when these touch ground or are confronted by cooler temperatures that water precipitates out and what we see is huge storms of long duration and the potential for much greater flooding events."

Anna: "So, what you're saying is this part of a blot or pattern across North America."

Bob Sanford: "Well, unfortunately, this may be the new normal. I regret to say that everything we know about how climate affects the hydrologic cycle supports or suggests that events like this are likely to be more common. And the insurance industry has already warned us of a trend towards more intense and longer duration storms that cause more damage especially in areas of population concentration. And this is certainly what we're seeing in the Calgary Area."

Anna: "What are you hearing from people you know in Canmore?"

Bob Sanford: "Well, there's a great deal of concern about how long this event is going to last and, well we heard from residents there this morning on your show, there is a deep concern about how much damage there has been done to very expensive infrastructure, roads and bridges. So we're going to have to wait until the storm is over to determine exactly the extent of those damages."

Anna: "What should we be doing to address the situation you're describing?"

Bob Sanford: "Well, I think that it's important to recognise that the loss of hydrologic stability is a societal game-changer. It's already causing a great deal of human misery widely. So we're going to have to replace vulnerable infrastructure across the country with new systems designed to handle greater extremes and this is going to be very costly. We're also going to have to invest more in the science so that we can improve our flood predictions."

Anna: "As you look at what's unfolding across Southern Alberta - not surprising to you? Surprising? The residents there certainly are saying it was completely unexpected."

Bob Sanford: "Well, I don't know if it was entirely unexpected. We know that there's great variability in our climate naturally. But we also know that some of these influences are affecting the frequency of these storm events. And researchers at University of Saskatchewan's Kananaskis research centre  have predicted already that events of this sort will be more common.

No-one likes to be right on such matters, but it appears that these are going to be events that we're going to see more frequently in the future."

Anna: "Um-hmmm, that's a rather grim forecast. No pun intended."

Bob Sanford: "It is grim, but I think that if we accept what we see happening right in front of our very eyes is real then we can begin to adapt and begin to rethink about how we situate our homes and our infrastructure and flood plains. We can begin to think about how we're going to adapt to more extreme weather events it's not certainly outside of the domain of human possibility to do so and we should be acting toward that direction."

Anna: "Well Bob, good to talk to you. Thanks for your time this morning."

Bob Sanford: "Thank you."