The fork in the road: Climate change here to stay

Hey there, time traveller!
This article was published 19/8/2014 (1887 days ago), so information in it may no longer be current.

The summer lament of Winnipeggers is all too familiar. Mosquitoes are flying, and the Forks is flooded. The Forks is Winnipeg's premier tourist destination and an important part is the river walk. A flooded walkway reduces foot traffic and hurts business. Five years ago, Premier Greg Selinger promised — perhaps unwisely — to solve the problem. But even a premier cannot hold back the rain. Politicians can talk the talk, but we're still not walking the walk at the Forks. It has fallen victim to a problem so large, so pervasive that even Mr. Selinger cannot fix it: our rapidly changing climate.

For Manitobans, climate change is not something in the distant future that we might avoid if we all start driving electric cars. It is right here, right now. Get used to it.

Manitoba's climate, with its short hot summers and long cold winters, is among the most extreme in the world. It is also among the fastest changing. Mother Nature has announced this in a full-throated voice, sending us two "one-in-300-year" floods in the last four years in the upper Assiniboine region.

Our more frequent floods are directly attributable to precipitation that has risen sharply during the spring and winter in recent decades. In southwestern Manitoba, for example, spring precipitation has increased between 30 per cent and 50 per cent since 1971.

Winnipeggers are living it, too. Over the same time span, average May rainfall has doubled. Higher river flows and more frequent flooding are the result. And as though that were not bad enough, it is going get worse. The Intergovernmental Panel on Climate Change (IPCC) forecasts that our climate will get even wetter during winter and spring over the next four decades.

Look out.

Our flood infrastructure was built in an earlier, drier era and its shortcomings are already painfully clear. The Portage Diversion that diverts the Assiniboine River into Lake Manitoba was completed in 1970.

Twice in the last four years it has been used far over its original design capacity, and only extraordinary efforts during both flood emergencies kept the structure intact.

When the diversion was built, hydrologists and engineers did not foresee that it would be used so often and so heavily. They expected an expanded Fairford Water Control Structure (completed in 1961) that drains Lake Manitoba to handle the artificial inflow from the diversion.

But it can't. It's not even close any more.

The Portage Diversion surcharges Lake Manitoba and has created massive and expensive flooding twice in the last four years. This is just one of the symptoms of climate change in Manitoba. The question is, what do we do about it?

Strategies to cope with climate change fall into two broad categories: prevention and adaptation.

Under prevention we take steps to reduce reliance on fossil fuels that generate greenhouse gases; we deploy carbon-capture technology to reduce carbon dioxide emissions. This might help prevent climate change tomorrow.

Under adaptation, we focus on today. We adapt to the current effects of climate change. We switch to drought-adapted crops, or use more irrigation with drier summers; higher peak river flows mean higher dikes or water storage reservoirs.

In an ideal world, prevention would eliminate the need for adaptation. That would have required considerable foresight and probably would need to have started about the time of the Industrial Revolution. We didn't, and climate change is already here. And it arrived sooner in some places than others. Manitoba is one of those places.

The prospect of increased river flows requires immediate action if we want to avoid paying bigger and bigger bills for more and more flood damage. And while climate change is our biggest problem, increased runoff from the landscape due to urban and agricultural drainage is a close second. It exacerbates the effects of climate change.

Some needed adaptations are already clear. Lake Manitoba and Lake St. Martin, for example, require expanded outlets to alleviate artificial flooding due to the Portage Diversion. Engineered solutions though tend to create new problems of their own.

Brandon, for example, requires better flood protection. But every dike built to protect people and property upstream makes the flooding worse downstream.

What is urgently needed is a "Back to the Future" solution: Increasing water retention on the landscape, especially by restoring drained wetlands that do this naturally. It can often be done very cheaply, as simple as filling in a drainage ditch. This also has the added benefit of removing excess nutrients such as phosphorus from the water. Research by Ducks Unlimited suggests that wetland restoration in southwestern Manitoba would add the rough equivalent of two extra Shellmouth Reservoirs.

We've spent a great deal of time and resources on engineering megaprojects to move water around in Manitoba. It's now time for an environmental megaproject, one built through the cumulative construction of many microprojects for water storage.

Wetland restoration should be at the centre of this effort. The equivalent storage capacity of even one extra Shellmouth Reservoir would look pretty good right now.

For Winnipeggers, the most obvious consequence of climate change is our chronically flooded walkway at The Forks. Some suggest that we should use our purpose-built flood control structures such as the Floodway and Portage Diversion to make the walkway more accessible. This is not the solution. These structures, especially the diversion, have enormous social, economic and ecological costs associated with their use. Just ask Lake Manitobans.

There is a simpler and obvious solution. Adapt.

Even the most powerful politicians cannot hold back the rain. But they can plan for a rainy day. With higher spring and summer river levels now the new normal, lowering river levels is going to be harder than ever. So build the walkway higher. Rack up the cost to our changing climate.

 

Scott Forbes is an ecologist at the University of Winnipeg. One of his current research projects is examining the effect of weather and climate on wetland birds.