This is largely an artifact of the fact that temperature proxies are natural low pass filters. CO2 has increased faster than this several times during volcanic outbursts. People using the contrast between smoothed archaic curves and sharp modern curves and saying this has never happened before are either disingenuous or don't understand basic data analysis. Either way, proceed with caution!
Discussion
I totally acknowledge and know that atmospheric CO2 levels and global temperatures have risen sharply in the past due to volcanism or asteroid impacts. And guess what? Those events coincide and correlate with mass extinction events. I am not making the claim that this is unprecedented, I'm saying it's concerning and why we don't generally include periods of time when the earth was warmer due to natural, slow cycles in the conversation about climate change because it's more comparable to other times in history when CO2 levels and temperatures rose sharply.
Oh, I agree, the "well the dinosaurs were fine at 2500 ppm" claim is ridiculous. But equally ridiculous is the idea that 800 or 1000 ppm for a century or a millenium would definitely bring about catastrophic warming. And yeah, precautionary principle applies, but the problem with that is the precautionary side is starting like $100T in the hole in terms of annual value.