So much of the reporting on how the climate crisis is affecting water systems has centered on shrinking sea ice, glacial melt, and sea-level rise that it’s easy to forget that the crisis impacts every drop of H2O on the earth’s surface.
From the tiny stream in your grandmother’s backyard that you played in as a child to the mighty rivers that transport goods, power towns and cities, and provide recreation and fresh water to millions, waterways large and small are being transformed by climate change – and far quicker than even experts had predicted.
This spring, scientists studying Arctic river ice revealed what is being described as “the first case of large-scale river reorganization as a result of human-caused climate change,” according to the Washington Post.
The scientists discovered that in mid-2016, the rerouting of meltwater from the Kaskawulsh glacier in Canada’s Yukon Territory, which has been rapidly retreating because of Arctic warming, caused a dramatic change in the flow of two rivers. The melt once fed the Slims River, which flowed north into the Bering Sea. But over the course of just four days, the melt changed the drainage gradient of the glacier just enough that it began channeling its meltwater into an ice canyon that carried it away from its previous flow into the Slims and toward the Kaskawulsh River, flushing freshwater southward into the Gulf of Alaska and reducing the Slims to a trickle.
This is just one example of the major changes happening to rivers and streams all over the world as temperatures rise and precipitation patterns change. Read on to learn more.
Drought and Flooding
You can look at climate change’s impact on rivers as a case of feast or famine. Warming is fundamentally altering the water cycle and shifting precipitation patterns. In many areas, rainfall has become either increasingly abundant or in desperately short supply, relative to longtime averages.
To fully grasp the impact this might have on a river, you should start at its literal source. If the glacial meltwater or high-elevation snowmelt that constitute the headwaters of many rivers diminishes because of warming and ever-lessening annual precipitation, the entire river system begins to dwindle.
In Bolivia, this situation was a significant contributor to the complete disappearance of the nation’s second-largest lake, Lake Poopó. The evaporation of the lake has been attributed in large part to the climate crisis-fueled decline of the Andean glaciers that fed the lake’s tributaries.
Conversely, extreme weather events that dump excessive rainfall on headwater regions can cause devastating floods far from the source of the heaviest precipitation as rivers swell and the floodwaters disperse all the way down the system.
The feast-famine scenario created by changing long-term precipitation patterns, severe storms, and evaporation attributed to overall warming has parallel impacts on the quality of river water.
Extreme rainfall events lead to a lot of runoff because the soil simply isn’t able to absorb the precipitation at the rate it’s falling. In urban, suburban, and agricultural areas, this runoff will pick up pollutants from the landscape and carry them to nearby rivers and other waterways. Additionally, in many older communities, storm water runoff and sewage are transported together through the same single-pipe system. Extreme rain events can overwhelm these systems, spilling raw sewage and polluted storm water into nearby streams and rivers.
“Impaired water quality is a global and growing problem, limiting resources for drinking, domestic use, food production and recreation, as well as harming ecosystems,” Nature writes.
On the other end of the spectrum, frequent droughts, enhanced evaporation, and decreases in overall annual rainfall result in reduced water levels in streams, rivers, and lakes, which leaves less water to dilute even relatively common pollutants.
It goes without saying that rising levels of pollution – whether from too much or too little precipitation – will create a major strain on any ecosystem that relies on the freshwater provided by streams, rivers, and lakes, threatening the survival of many fish, plant, and wildlife species. Of course, there are also major implications for drinking water as well.
What Can I Do?
With all this in mind, the White House’s recent proposal to cut the Environmental Protection Agency’s budget by more than 31 percent is especially disheartening. The EPA is tasked with enforcing America’s clean water laws, after all, and those regulations will become even more vital in a world where changes in our climate further compound existing pollution concerns.
Budgets reflect priorities, and any budget that scales back efforts to protect our rivers and streams makes it clear that, to this administration, the bottom lines of Big Polluters are more important than the health and well-being of Americans.
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