Imagine a glacier floating towards a strait. If it turns one way it’ll pass through. If it turns another way it will get stuck. This blocks ice and lets the colder water pass. This ice free body of water absorbs light 1/16th the maximum estimated CO2 effect which is 1 w/m2.
Imagine 20,000 leagues below the sea a cave which lets water pass through gets clogged with a whale. This changes the tragejectoy of the ocean currents which are poorly understood and have an error bar forcing?