I do not think anyone has made that crazy of a claim. There is a certain amount of water needed to prevent salination, that is a real thing. If not enough water is flowing out of a river, the salt water begins running up the river within reason, and salting the land.
YOu are correct and
@zymurgy is a simpleton who simply cannot comprehend the arguments he reads.
At no point in this thread did i say or even suggest 'runoff was bad... not needed, etc' or any thing zymurgy imagined in his head.
What i did address is the MASS AMOUNTS more glacial runoff that is now reaching the sea and ALREADY changing the salinity mix in those coastal areas for good or bad.
it is simple fact that the levels of run off now are exceeding what we have for most of mankind's time on this planet and if we had anything resembling full glacial collapse then the planet would be entering a "greenhouse" climate state, most closely resembling the Early Eocene Epoch.
I am not making arguments to that extreme, but rather addressing the CLEAR trajectory we are currently on and how CURRENTLY this is already happening.
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Ai Summary:
Increasing fresh glacial runoff is actively and significantly changing ocean coastlines right now. However, this transformation is happening through three very different—and sometimes surprising—mechanisms depending on where you look on the planet. [
1,
2,
3,
4]
1. Global Coastal Inundation (Sea Level Rise)
The most widespread change is the physical push of the global ocean boundary inland. As mountain glaciers and polar ice sheets melt, they pump hundreds of billions of tons of fresh water into the sea annually. [
1,
2]
- The Rate: Global sea levels are currently rising at an accelerated rate of roughly 3.94 millimetres per year. Together, mountain glaciers, the Greenland Ice Sheet, and the Antarctic Ice Sheet account for over 50% of this total rise (the rest is driven by the thermal expansion of warming seawater). [1]
- The Impact: On low-lying coastlines, such as the U.S. South Atlantic coast or Bangladesh, this marginal vertical increase translates to a horizontal retreat of beaches and dunes. It is dramatically amplifying the inland reach of high-tide "nuisance" flooding and storm surges. [1, 2, 3]
2. "Exposing" New Arctic Coastlines
In the far north, glacial runoff is altering coastlines by physically
creating new land. [
1]
- As massive marine-terminating glaciers shrink back toward the land, they leave behind freshly exposed bedrock and gravel.
- Satellite data has revealed that retreating Arctic glaciers created roughly 2,500 kilometres of brand-new coastline and dozens of new islands.
- These newly exposed "paraglacial" coastlines are highly unstable, prone to massive landslides, and lack established ecosystems. [1, 3, 4, 5]
3. Rapid Erosion and Collapse
In areas where glaciers melt from the land and flow out as rivers (such as northern Canada, Alaska, and Siberia), the sudden surge of fast-flowing, warm freshwater runoff destroys existing ocean shorelines. [
1,
2,
3,
4,
5]
- Permafrost Thaw: The rush of warmer river water thaws the frozen coastal permafrost that acts as a structural "glue" holding the shore together. [1, 2]
- Loss of Sea Ice Protection: Because nearby sea ice is disappearing, coastlines lack a buffer against incoming ocean waves. Combined with high-volume glacial river runoff, sections of Arctic coastline are collapsing and eroding into the ocean at rates of up to 40 metres per year. [1, 2]
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