Ice is water in solid form. When it melts, it dissolves into liquid. There is nothing chemically remarkable about this. What is remarkable is the scale and consequence of the current melt.
The Greenland ice sheet contains enough water to raise global sea levels by approximately 7.4 metres. The West Antarctic ice sheet contains another 3–5 metres. Both are melting at accelerating rates. Glaciers are retreating on every continent. Arctic sea ice is diminishing in extent and thickness. The permafrost — permanently frozen ground that covers much of Siberia, Alaska, and Canada — is thawing, releasing methane and carbon dioxide as it dissolves.
The consequences of this dissolution are global. Coastal cities — New York, Shanghai, Mumbai, London — will be inundated or require extraordinary defences. Low-lying nations — Bangladesh, the Maldives, the Marshall Islands — may cease to exist as habitable territories. Hundreds of millions of people will be displaced. The dissolution of ice will dissolve the geography on which human civilization was built.
The process is not reversible on human timescales. Even if all greenhouse gas emissions ceased tomorrow, the ice would continue to melt for centuries, driven by the heat already absorbed by the oceans. The dissolution has momentum. We are watching the beginning of a process whose end we will not see.
In Fiction
Kim Stanley Robinson's New York 2140 (2017) imagines a New York City partially submerged by sea level rise. The water does not dissolve the city — it transforms it. The streets become canals. The skyscrapers become islands. The dissolution of the coastline is not an ending but a reorganization. Robinson's optimism is qualified: the city survives, but millions of others do not.