How global warming will melt our glaciers, empty the Great Lakes,
force Canada to divert rivers, build dams, and, yes, sell water to the United States
· paintings by Stephanie Aitken
Certainly Canada is in no danger of running out of water. In fact, the spring rainstorms I drove through in Alberta, flooding both the Elbow and Bow Rivers in Calgary, were harbingers rather than anomalies. But the distribution of water “wealth” and “poverty” is changing: areas like northern BC will have more than they know what to do with; others, like the Great Lakes Basin, will turn dry. Despite the challenges, the implications are only starting to gain traction with policy-makers. In BC, where weather changes more pronounced than anywhere else in Canada outside the Arctic can be traced back decades, the present holder of the ninety-four-year-old office of Comptroller of Water Rights has only recently turned to the issue. “The science is ahead of the policy,” Jim Mattison concedes.
But those whose livelihoods are on the front line of the new weather fronts are becoming impatient. In the Kootenay mountains of southeastern BC, Kindy Gosal, a manager with the Columbia Basin Trust, is emphatic: “Climate change is happening,” he asserts. “It’s changing our landscapes and changing our ecosystems. We can see glacial recession. I’ve lived in this place for over thirty years and can see, from when I first hiked up to these places, that these suckers are going back. The question is, what do you do about it?”
A couple of mountain ranges away, Okanagan Valley orchardist Lorraine Bennest straightened from a shallow ditch where she was installing irrigation pipe to scan several thousand apple saplings she had just planted. Small, wiry, and fierce, Bennest scowled beneath the straw hat covering her steel-grey hair. Her new orchard cost $30,000 an acre to plant, and she hopes to turn a profit by 2012. But she’s worried: winter snow is disappearing from the hills above her orchard in Summerland ( just north of Penticton), and the valley’s growing population is putting new demands on Trout Creek, the village water source, which depends on winter snows. “If we’re going to run out of water,” Bennest says, “don’t talk to me in twenty years. Talk to me now!”
Differentials of temperature, humidity, and salinity drive primeval currents in a meandering global courtship of ocean and air that, broadly speaking, transports heat from the tropics to the frozen poles. In this Gaia dance, rain and snow are accidental by-products of thermodynamics — “precipitates” shed when stateless air masses cross invisible boundaries of dew- and frostpoint. Now, rising temperatures are heating up the tempo of this global dance. As melting ice dilutes salty oceans, clouds vanish over disappearing forests. Greenhouse gases and industrial smog are also reformulating the atmosphere, and, perhaps, as the planet tilts on its axis, or flares of charged particles lick out toward us from the sun, the differentials that drive the dance are changing places.
Scores of researchers have been recording visible changes in local climates, from the number of floods in Newfoundland to the annual evaporation of water from Great Slave Lake. Three substantial efforts have surveyed this growing body of science. Climate Change Impacts and Adaptation: A Canadian Perspective, prepared by Natural Resources Canada, and Environment Canada’s Threats to Water Availability are thorough analyses of climate change. Vulnerability and Adaptation to Climate Change, jointly published by Global Change Strategies International Inc. and the Meteorological Service of Canada, drills most deeply into the underlying research.
All three documents maintain that as temperatures rise, there is actually more water, not less, coursing through the global heat pump — a result of the thawing of glaciers and ice sheets. More water plus more energy, traversing the same geography over the same period of time, means storm fronts pack a heavier, wetter, hotter punch. But that doesn’t necessarily lead to more water in lakes and rivers, because warmer temperatures are also inducing dramatic increases in evapotranspiration (ET) — science’s word for water breathed out by plants and vaporized from lakes and streams. In the central areas of the country, evaporation is taking place faster than precipitation, not only sucking any extra rainfall back into the air, but also drying out lakes, reservoirs, and fields. The extreme humidity caused by evaporation that plagued much of central Canada this summer may be a dramatic example of what is to come. “We’re in for an accelerating set of trends beyond what we’ve seen since 1970,” says Ottawa hydrologist James Bruce, lead author of the Meteorological Service of Canada study. “They’re scary.”
How weather patterns will finally settle down is not entirely in focus. But the outlines are unmistakable: more rain and snow in the northern Rocky Mountains, while the Prairie and Great Lakes regions dry out. In almost every region of the country, global warming is leaving behind less snow and piling more rain into fewer late winter and spring storms, which are followed by longer, warmer, drier summers. The effects are least pronounced in Newfoundland and Labrador, where temperatures have actually cooled by 0.7°C in the last fifty years. Precipitation, on the other hand, has been increasing, but almost entirely due to greater winter, spring, and autumn snowfalls. Despite this, many rivers in the region experience lower flows in late summer.
With more land mass than any other province, and 3 percent of the planet’s fresh water, Quebec reflects the national conundrum of higher average precipitation with less water available in populated regions. The province has enjoyed relatively large increases in rainfall and snowfall during the last century. But the Meteorological Service concluded that most of that has come in Quebec’s northern reaches, while more than 95 percent of Québécois live in the St. Lawrence River watershed in the south.
For more than twenty years, scientists have tracked conditions at dozens of lakes upriver from Montreal, in the northwestern portion of the Great Lakes Basin. “During this period,” the Meteorological Service noted, “air temperature increased, precipitation decreased and average annual evaporation increased by approximately 50 percent.” The cumulative effect on flows out of the lakes to the St. Lawrence may be dramatic, with the river losing up to 40 percent of its volume at Montreal. Any drop in water levels in the Great Lakes approaching that scale will send shock waves through the country’s richest economy. “I worry about the fact that hydro power production in the Great Lakes system has been declining [because of falling water levels] and will probably continue declining,” says Bruce. “So they’ll have to fire up more coal- or oil-fired generation, or gas-fired, further increasing greenhouse-gas contributions.”
The comparative simplicity of the Prairie economy provides little comfort. Projections are for less winter snow, but increased spring rains will fail to offset faster summer evaporation, leading to drier soils and less water in streams. “In the past thirty years,” the Meteorological Service found, “trends have become more significant . . . . Things are changing more rapidly.” In fact, during the region’s most recent drought, in 2001, Saskatoon was 30-percent drier than at any time in the last 110 years.