Climate Change and Freshwater
Climate change (really, climate disruption) manifests most spectacularly in its impact on freshwater. Shrinking snow packs, erratic rainfall and increases in extreme weather events alter formerly predictable patterns and dramatically impact river function and flow.
Most Oregonians live in the wet and rainy northwestern quadrant of the state – basically, the Willamette Valley. Statewide, virtually all Oregonians enjoy a reliable supply of household freshwater (the tap works when you turn it on). These simple facts make the idea of a freshwater crisis intangible for many, but no less real. Over the next 30-40 years, climate disruption will amplify the stress on freshwater systems by orders of magnitude. In the Pacific Northwest:
- A reduction of more than half the snowpack by 2040, having broad impacts. Glacial runoff provides for not only aquatic habitat, but irrigation, drinking water and hydroelectric power.
- A decrease in streamflow of at least 50 percent during summer months in many rivers and streams by mid-century.
- A negative impact on salmon and other anadromous fish due to increased winter flooding, reduced summer and fall streamflows, and warmer stream and estuary temperatures.
- A decrease in water quality due to higher temperatures, increased salinity and pollutant concentration by mid-century.
- Sea level rise will increase saltwater intrusion into groundwater in some regions, affecting drinking water and agriculture in coastal zones.
- An increase in evaporation will reduce effectiveness of reservoirs.
- An increase in extreme weather events and more erratic rainfall means more water falls on hardened ground unable to absorb it, leading to flash floods instead of replenishment of soil moisture or groundwater levels.
What can we do about all of it? Amplify and accelerate efforts to restore weakened aquatic systems while preserving existing, high-functioning ones. Speed matters here. It’s not too late to act. There is a ton of work to do, much of it easy, with huge potential, positive impact. We just need to get it done.
(for sources on impacts of climate change on freshwater, email Alan Horton directly and he will be happy to forward source material to you)
- Alan Horton's blog
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