All eyes are on the future of fresh water after a winter of record heat
After a winter that smashed heat records, re‐ searchers around the wor‐ ld are taking a close look at how human disturbances and the rapidly changing climate are affecting the world's freshwater supply.
"We're reducing both wa‐ ter quantity and water qual‐ ity," says Katrina Moser, an associate professor from Western University's depart‐ ment of geography and envi‐ ronment. "Some places are having a bigger impact on quality. Some places, we're having a bigger impact on quantity. But that double whammy is going to really af‐ fect water availability to us moving into the future."
While our planet is cov‐ ered in water, 97 per cent of it is salty, with only three per cent as fresh water found in glaciers, rivers, lakes, wet‐ lands and underground aquifers. It is vital to support our environment, our food and our health.
Canada is home to 20 per cent of the world's fresh wa‐ ter. But less than half of that is accessible, and an even smaller fraction is available to the bulk of Canadians liv‐ ing near the southern bor‐ der.
"How fortunate we are in Canada to have so much fresh water. And I think we often take that for granted," said Moser.
"And so with that incredi‐ ble fortune [and] privilege, al‐ so comes the responsibility to protect that water."
Altering the water cycle beyond recognition
A recent study out of Finland analyzing freshwater re‐ sources around the globe found that humans have been pushing freshwater sys‐ tems far beyond the stable conditions they need to func‐ tion normally.
"We really should start to see the global water cycle for what it is. It's a global, crucial aspect of the Earth system that we all depend on," said Miina Porkka, an associate professor from the University of Eastern Finland, who led the study. "All life on Earth depends on that. And so it is our shared responsibility,"
The water cycle is the pro‐ cess by which water evapo‐ rates off of land and ocean, is stored in the atmosphere and comes down to Earth as precipitation. It then filters through lakes, rivers, or groundwater systems, and then eventually is evaporated up into the atmosphere again.
But, Porkka said, humans have been altering it with dams, large scale irrigation systems, deforestation and the removal of wetlands, so the conditions that are re‐ quired for the ecosystem to function normally are no longer being met.
"We know that ecosys‐ tems have adapted to specif‐ ic variability."
"You may start having se‐ rious ecological impacts, seri‐ ous impacts on the cycling of water itself, and that could then turn into serious ecolog‐ ical impacts elsewhere, not just in that current region."
And of course, there's the effect of climate change.
After a record-breaking warm winter, most of Canada experienced a deficit of snow, according to David Phillips, senior climatologist at Envi‐ ronment and Climate Change Canada.
"Whatever [snow] people got didn't stay because it was so warm. From a water re‐ source standpoint, you want it to stay, and instead it melted away," said Phillips.
Snow acts as a reservoir, slowly releasing water through the spring and early summer. This melt provides water for more than one bil‐ lion people worldwide. But a warmer climate is changing how that process works.
"The snow is warmer, the temperature at which it's falling is warmer, and then you have constant air tem‐ peratures that are warmer," said Christina Aragon, a PhD student at Oregon State Uni‐ versity. "Snowpacks aren't functioning as natural reser‐ voirs to the degree that they were in our past."
In a recent study, Aragon and her colleagues found a 22 per cent decrease in the amount of water being stored in snowpacks in the mountains of the United States over the past 40 years.
"As a water researcher, I think it is pretty discouraging, but highly motivating for tak‐ ing action on climate change," said Aragon.
Less water downstream, combined with warmer tem‐ peratures, can lead to drought, wildfires and water quality issues with the water that remains.
"When we remove ice cov‐ er, we give more time for wa‐ ter to evaporate," said Kat‐ rina Moser from Western University. "We can see lake levels decrease and salinity increase. And if you change salinity even a tiny bit, that can have profound impacts on the organisms that are liv‐ ing in those lakes."
But the effects of climate change vary from place to place, she says, even within Canada. While the Prairies and west coast are experi‐ encing less precipitation, pre‐ cipitation in Ontario is ex‐ pected to increase, which could lead to flooding, in‐ creased erosion, and nutrient runoff. This, in turn, could lead to harmful algae blooms developing, which can choke out life in a waterway.
Groundwater declines but with a ray of hope
While most of the world's fresh water is locked up in glaciers, the largest quantity of available fresh water can be found buried below the surface.
"Groundwater is every‐ where under your feet on the landscape. At some depth, if you started digging, you would reach groundwater everywhere on Earth," said Scott Jasechko, associate pro‐ fessor at the University of California, Santa Barbara's Bren School of Environmen‐ tal Science and Management.
Groundwater is a crucial resource for our planet; 10 million Canadians rely on groundwater for drinking wa‐ ter. It also supplies nearly half of the water used for irri‐ gation projects around the world.
But this high demand makes groundwater the world's most extracted raw material; 70 per cent of global groundwater with‐ drawals are used for agricul‐ ture, whether that be for growing food, industrial crops, or growing livestock.
For recent study, Jasechko and colleagues looked at groundwater levels in almost 1,700 aquifers in more than 40 countries, and analyzed how the water lev‐ els were changing over time. They found that - in most of the aquifers - groundwater levels were declining faster than the water cycle could re‐ plenish them.
And while the researchers didn't see significant declines in Canadian groundwater, Jasechko said Canadians still aren't off the hook.
"Demand for that ground‐ water can be driven by inter‐ national markets," he said. "Canada imports about $5 billion of food from California alone every year. And that demand for food leads to groundwater pumping in Cal‐ ifornia, and we're seeing some rapid rates of ground‐ water level decline in Cali‐ fornia."
aGroundwater depletion is not an inevitability. Scott Jasechko, Univer‐ sity of California Santa Barbara
However, several of the aquifers weren't declining, and in fact had shown signs of recovery.
"We did find some rare cases where groundwater levels were declining in the 1980s and '90s and have re‐ covered in the 21st century.
These cases are rare, but I think they provide illustrative examples of how we can make things better."
These examples include policy changes, redirecting of water, and infrastructure projects called leaky lakes, which are lakes purposefully built to collect water to feed aquifers.
Ultimately, Jasechko said he wants people at both the governmental level and indi‐ vidual level to be more con‐ scientious about groundwa‐ ter usage.
"The big lesson that we can take away from this is that groundwater depletion is not an inevitability," he said. "Humans have agency, and there are interventions we can put in place to turn things around and fix this problem."