Climate change will force us to reconsider how we are managing our water resources

Andrew Fazekas
Weather and Science writer

We all love our water, and as Canadians we are proud of our rich abundance of pristine lakes and rivers. After all, only half-of-one-percent of the worlds population has some 20% of the global supply of freshwater; definitely something to crow about and protect, right? However, there is an underlying worry that this clean resource may come under siege in the coming decades across the nation.

Climate change is poised to affect this precious commodity, which might cause Canadians to face a deteriorating water supply. While the global effects of climate change are generally accepted amongst the scientific community, its the effect of this environmental phenomenon on a regional scale that are definitely more uncertain.

Andrew Fazekas is a science and weather expert for Yahoo Canada News.

Water levels will rise and fall in different regions which will impact our society – everything from food supply, industries and economy, says Hanspeter Shreirer, senior watershed management scientist at the University of British Columbia in Vancouver.

Ontario alone is home to nearly 250,000 lakes and about one-third of the world's fresh water, mostly in the Great Lakes. And nearly 20 million people in Ontario and neighbouring Quebec that depend on these waters, for not only drinking, but farming and industrial uses as well.

Through the use of Global Climate Models, regional historical data and other methods, scientists are coming up with sobering scenarios of how ecosystems and economic regions will start being affected by climate change in the not-so-distant future. Already researchers see clear evidence that were getting more environmental variability. But Shreirer and his colleagues worry that the public may not be getting the right message in terms of climate change and its effects that they actually will feel.

I think we made a mistake telling the public that its going to get two to three degrees warmer on average, because to most of us think thats totally meaningless. You probably wouldnt notice a difference going from your house to the car, anyway, Shreirer explains.

But more likely what will concern you is if it's too wet or too dry, and now theres significant evidence all over the place that this variability is increasing.

One of these big variables already ocurring is the higher frequency of very intensive storms and the resulting flooding in large urban settings.

Our ever-expanding concrete jungles mean that there will be far more issues with water runoff, since weve made all the surfaces impervious, Shreirer says. That results in eroding more material and much more pollution.

“Look at Toronto, I think theyve been flooded three or four times in the last four years, as has Calgary,” he says.

“Its not a problem normally, but its when you get these kinds of big events more often, thats when it gets rough for everyone.”

In general, it's expected that as more pressure is put on our water resources by climate change, there will have to be a certain balance in competing uses, and the needs of the aquatic ecosystems cant be forgotten. For instance, as water temperature is expected to rise in our rivers, certain species of fish, like the Pacific salmon, may experience a disruption in their spawning activities.

Water resources support so many important human water uses, like sanitation, irrigated agriculture, hydropower, and water for cooling thermal power stations and mining. Unfortunately, however, we also use water to dispose of many of our wastes too.

Warming waters in lakes are expected to cause significant damages to the aquatic systems in many large bodies of water across Canada.

It all has to do with increase in the incidences of excessive algae blooms that choke off all life in the water, known as eutrophication.

While some of the blame for these increasing blooms are currently related to runoffs from agricultural activitiesand use of fertilizers, the expected warming of the lakes will also be a major contributor,said Madjid Mohseni, an environmental researcher at the University of British Columbia.

Climate change and increased episodes of major events (like floods) go hand in hand, and can cause erosion of lands around the lakes, which in turn affect the quality of water in lakes and rivers, too.

All of the world's developed nations are facing problems of water quality associated with nutrient pollution, and Canada is no exception. In the East, Lake Erie has been affected in recent years, while in Western Canada the notable example is Lake Winnipeg. In 2007, there was an algal bloom that covered 15,000 square kilometres of this giant body of fresh water.

What causes these incidents are nitrogen and phosphorus  both of which originate from human sewage and agriculture, where it is found in commonly used livestock wastes and inorganic fertilizers.

Excess nutrients affect ecosystems, and the resulting algal blooms in our lakes can cause major problems in water treatment. Blue-green algae can be highly toxic and can affect human health and even cause death in wildlife.

Aquatic toxicologist Douglas Holdway agrees that big changes will be coming with climate change  and some have already started. The very basic chemical and physical characteristics of our fresh water is already being altered.

“Warmer water holds less oxygen, and basically thats going to direct the changes associated with global warming,” says Holdway, a senior researcher with the Canadian Water Institute.

“So whats really at risk is initially the distribution of our cold water fish, where we’re starting to see warm water fish where we’ve never seen those species before, moving north. And the cold water fish are moving farther north again. But when we get to the Arctic, the fish there will have nowhere to go.”

With shrinking glaciers and sea ice, climate warming has already had dramatic effects in Canada.

In Western Canada, we are already seeing changes in the balance between snow and rainfall.

Experts expect this to lead to changing river flows, with smaller snowpacks and earlier melt changing the seasonal patterns of river flows.

The prairie flooding of 2014 was extremely unusual normally prairie streams flow in response to spring snowmelt, but these floods were generated by summer rainfall,explains Howard Wheater, Director of the Global Institute for Water Security at the University of Saskatchewan.

These are the kinds of changes we expect to see more of, and they will influence extreme events like floods and droughts as well as average conditions.

In general, the effects in Canada are only poorly understood. For example, Wheater points out that in the Prairies, there is a fine balance between water availability from precipitation and evaporation. A warmer and wetter future will probably mean that crops will be changing along with more frequent floods.

There is no doubt we are changing our environment in many ways, and extreme events will be affecting increasing numbers of people, so we are going to have to have more rigorous water management practices in place, he says.

The only certain thing about the future is that it is quite uncertain," Wheater warns. "And so that means following strategies that are flexible and allow for adaptation. We will for sure live in a warmer world, but we may very well be affected more by extreme climatic events.

Canada has tremendous water resources and the human potential to manage change effectively. However, there will be wake-up calls for policy, and these will no doubt be triggered by coming extreme events.