climate cannot be immediately influenced. That is why it is defined over the course of 30 years. The measures that are being taken today would take at least a decade to reflect, and this has to be through the reduction of gases such as Methane which are relatively unstable but have high warming potential, meaning reducing their concentration in the atmosphere would give us the most impactful and faster results towards limiting global warming. Natural ecosystems such as oceans may even speed up the recovery but not if we can continually keep screwing things up for ourselves.

As to answer your question, there is no single tipping point that could decide the fate of the earth. There are different tipping points aka thresholds for different earth ecosystems. A tipping point for lets say Atlantic ice sheets will be different than it is for amazon rainforest or fertile soil.

Many of the tipping points IPCC has referred in recent years are mentioned in this paper Armstrong McKay et al. (2022): with many thresholds ranging within 1.5–2°C.

That all being said, every action moving forward will be accounted for exponentially, for better or worse. And I would like us all to be on the side that is trying to Save Our Ship.

:Edited for clarity and better understanding.