To put an end to the warming trend by cutting emissions?
It isn't really "speculation". Pretty much every analysis confirms we passed that point somewhere in the aughts, at the latest. If we cut emissions worldwide to zero literally tomorrow, the climate would continue to warm for centuries, unless some heretofore unknown major factor inserts itself. For years, the argument's been to stop feeding more "fuel" into that warming "engine", to try and keep the pace of warming down to a level we could hypothetically adapt to over time.
It's also why discussions of carbon sinks are starting to increase, and people are trying to find increasingly cost-effective techniques to go about capturing that carbon out of the atmosphere. The latest idea I've heard is growing mass amounts of certain plants with a high carbon-capture ratio, harvesting them once they finish growing, bundling and compressing them, and then dropping the massive bundles that produces into the deepest parts of the ocean. Decomposition down that deep is
slow to potentially borderline nonexistent; the oceans already function as a carbon sink naturally through this process, where phytoplankton absorb carbon as part of their natural life process, and are either consumed or die themselves, the process of consumption eventually leading to the death of the consumer and it sinking to the bottom, where the carbon gets trapped.
Basically, this process, but accelerated through active human farming and dropping;
https://sitn.hms.harvard.edu/flash/2...limate-change/
We're already well past the point of preventing this. Now it's about damage control.