Interesting study linked to in the OP. Looking back in Earth’s geological history, there have been essentially two main temperature modes: one mode with mean planetary temperatures about where we are now and another mode where average temperatures are about 10 degrees C above this. The Earth has probably spent more time in this later balmier icecap-free mode.
I wouldn’t worry about the end of all life on earth due on global warming (CO2 levels have been multiples, ten times and more, of what they are now in the past, though usually when in this warmer temperature mode).
No doubt if we keep on the trajectory will go past a tipping point and head towards warm conditions like in the Paleocene-Eocene Thermal Maximum (PETM) around 50 million years ago. James Lovelock (British inventor/scientist and person who came up with the Gaia Hypothesis and going strong at almost 100 years old! ) had a series of books warning about the possibility of a sudden transition of this type. Would be extremely challenging to humanity to say the least (fairly sweltering near the equator, arable land moving a good deal northward plus oceans at least 70m higher when Antarctica melts). He’s rowed back a bit on that since (thinks the data just doesn’t imply an imminent transition like that).
Though I suspect we’ll reach a tipping point sooner or later on our current trajectory. Though that transition may possibly not be that sudden. If it takes a few thousand years (a blink of the eye in geological terms) humanity will probably have time to adapt (otherwise not so much).
I’d tend to agree with Lovelock that probably the only realistic fast way of greatly reducing CO2 emissions at the moment is widespread nuclear power (in spite of its many downsides): fusion seems permanently 20 years away and energy storage is still a real problem for renewables (they seem to need a fossil fuel-based power grid as backup).