Robert William Sandford - Flood Forecast: Climate Risk and Resiliency in Canada

Because it is so central to understanding what the floods in Alberta and elsewhere in Canada in 2013 mean to our future, it is important to explore more fully just what we know about our changing hydro-climatic circumstances. If you want to solve a crime or bust a bad bank, it is conventional wisdom that you follow the money. If you want to find out what is causing more-extreme weather events, you follow the water. To that end, it is important to identify key elements of the global hydrological cycle and follow the movement of water through that cycle. In so doing, we discover that water in the form of snow and ice plays a much larger role in determining global climatic conditions than many ever thought.

One of the most significant recent advancements in hydro-meteorology is the realization of how globally important the refrigerating influence of polar sea ice is. Three factors related to the extent and duration of Arctic sea ice have emerged as having great significance to the lives of every person on this planet. The first is the amount of heat required to melt sea-ice. The second is the potential effect of sea ice melt on ocean acidification and the reliability of deep ocean currents. The third is the profound influence of Arctic cold on the stability of weather conditions farther south and globally.

Water is an almost otherworldly substance. Once it is frozen it takes an enormous amount of heat to weaken the hydrogen bonds that hold water molecules in the rigid crystalline structure of ice. The amount of energy required to melt 1 kilogram of ice that is already at 0C is equivalent to the amount of energy required to raise the temperature of 1 kilogram of liquid water by 79C (the boiling point of water is 100C). From this we see why ice and snow are such effective climatic refrigerants. The problem, however, is that the moment after solid ice collapses into liquid water, all the heat you add afterwards will suddenly raise temperatures and increase evaporation.

Polar ice is now seen as a thermostat that governs major weather patterns globally. It is now feared that the decrease in the extent and thickness of sea ice could be the parameter that is feeding all of the increases that are causing concern over climate change. While there is annual variability in how much ice disappears each year, the area of Arctic sea ice that melted in 2012 was nearly the equivalent of the area of Canada as a landmass.

Sea ice is a thermal helmet without which climate warming can give the Earth system a shot straight to the head. If we lose the refrigerating influence of Arctic sea ice, global temperatures will skyrocket, with possible releases of methane from the permafrost zone that will further exacerbate warming. As I will point out later, evidence from Siberia suggests this may already be happening.

The loss of Arctic sea ice and the reduction of the extent and duration of snowcover in the northern hemisphere are reducing the temperature gradient between the pole and the tropics. It is this difference in temperature between the polar region and the warmer air to the south that largely defines the behaviour of the jet stream.

Observations of the jet stream have revealed that warmer atmospheric temperatures do not automatically translate into warmer weather. In a uniformly warmer and therefore more turbulent atmosphere, both warm and cold fronts end up and persist in places in the mid-latitudes where they were not common in the past, as mentioned earlier. Changes in atmospheric circulation patterns are pushing major subtropical storm tracks toward the poles, often causing floods of magnitudes we are poorly equipped to manage. This is also why we are seeing more and more widespread droughts and wildfires followed by major floods in the same river basins in the same year. Come hell and high water, if you will.

What we are also seeing is not uniform warming but the destabilization of historical weather patterns. People all around the world are complaining that the weather is all over the place, and theyre right: it is all over the place. Two years before the great floods in Canada in 2013, we believe we already knew why such extremes of weather appeared to be becoming more frequent.

Recent research has clearly demonstrated that in the Arctic and throughout much of the Canadian boreal, the quantity of water that had been trapped as sea ice and in glaciers, permanent snowpack and permafrost is in rapid decline. What is happening in the Arctic and in the North is exactly what is happening is much of the rest of Canada. Warming is causing the post-glacial hydrological wealth of Canada to change form. The water is not disappearing, however. Water doesnt do that. What is happening is that frozen water and liquid water are moving to different places in the hydrosphere: permanent ice and snow are becoming liquid water, and liquid water is evaporating. This is going to add additional edge to the already existing natural variability that characterizes weather and climate here and in much of the rest of Canada.

As I pointed out in my earlier book Saving Lake Winnipeg, the same warming that is causing permafrost to thaw in the North, glaciers to disappear in our western mountains and precipitation patterns on the prairies to change is also causing water left on the land after the last glaciation to evaporate. Research conducted at the University of Maryland demonstrates that lakes in northern Canada lost 6700 square kilometres of surface area, or roughly one-third of the area of Lake Ontario. Increasing evaporation also appears to be reducing water levels in the Great Lakes. So where is all this missing water going?

One of the places it is going is into the atmosphere, where it becomes available to fuel more frequent and intense extreme weather events. We are seeing this right across Canada as well as in Europe and elsewhere in the northern hemisphere. The algorithm upon which this assertion rests is one of the most basic principles in atmospheric physics: warmer air holds more water. The amount of water the atmosphere can hold increases by about 7 per cent per degree Celsius, or about 4 per cent per degree Fahrenheit. So whats the problem? The problem is that our entire built and agricultural environment, including urban water supply systems, stormwater infrastructure, roads, bridges and farms, are all designed for an earlier, more stable climate. These matters were already being discussed all over Canada long before the flooding occurred in Alberta.

Eight months before the flood: October 1519, 2012

In October of 2012 the University of Regina and the University of Texas at Austin, in association with the North China Electric Power University and the United Nations Water for Life Decade Partnership in Canada, hosted a major international conference around the theme Storm Warning: Water, Energy and Climate Security in a Changing World. The conference was held in Banff, Alberta, which provided an opportunity for a field trip that allowed participants to experience the spectacular Canadian Rocky Mountains and see through the eyes of experts what warming mean annual temperatures are doing to glaciers, snowpack and snowcover in Banff and Jasper national parks.

The invitation-only conference drew some seventy experts from the United States, Canada, Japan, China, Australia and Thailand to address six sources of significant uncertainty that will affect water, energy and climate security in the coming decades of the 21st century. Among other things, participants discussed what is known and what remains unknown about fluctuations in water availability and climate before and after the influence of human activity; and what can and cannot be learned from models or forecasts of climate based on downscaling from the global to the local, as well as insufficiently articulated feedback loops and other second-order effects. Experts also outlined what is known and not known about the real costs of adaptation to extreme climate events. Also on the agenda were ways in which global, regional and local governance systems and legal regimes adapt to uncertainty in water availability and climate fluctuations.