The present rate of CO2 increase is much larger than in past disruption events. However, the critical rate of change seen in past events is only part of the story. First. the timescale of the current situation (about a century) is much shorter than past events. Second, natural processes in the oceans tend to damp perturbations of CO2, at a roughly 10,000 year timescale. The upshot is that the critical rate of the modern event must be rescaled by a factor of about 100/10000 = 0.01 to be compared to past catastrophes. When that rescaling is done, our modern disruption event, if it continues throughout this century, looks fairly similar to the runup to extreme warming events of the past, including those associated with mass extinction. A rough estimate is that the tipping point would occur late in this century. For more detail, see our papers here and here.

But that too is only part of the story. If the tipping point is real, our own calculations suggest a roughly 10000-yr trajectory during which things become progressively worse—but only if there were no negative feedbacks beyond those we currently understand that would act to arrest the trajectory. And we would imagine that new technologies—or simply improved scientific understanding—might contribute towards goading the Earth system in the right direction.