There is no record of any warming even a fifth the speed of this one. That does not mean the climate warmed quickly. Slow warming often causes sudden transitions. We very much hope that such transition intervals are not somehow percentage locked to the interval of warming - we very much hope that a thousand year interval of climate change causing a hundred year ecological replacement interval does not imply that a hundred year interval of climate change will enforce ten year ecological displacements - because that would be disastrous for us. The global warming rate that contributed (along with the change in rainfall patterns and so forth) to the sudden ecological adjustment you mention has been measured. It was less than a tenth of the current global rate, IIRC - a couple of degrees C in thousands of years.