Realistically it would take a supervolcano or major asteroid impact to achieve such low-end radiative forcing scenarios, by injecting large volumes of material into the stratosphere and reflecting incoming sunlight, but any such event would be truly immediately catastrophic to human civilization (for example some major Yellowstone eruptions blanketed something like a quarter of continental North America with a meter of ash, IIRC), and would cause major crop failures and global starvation on an unimaginable scale. That would be worse for human civilization than any projected warming over the next century. Also, once the dust eventually cleared, the atmospheric CO2 levels wouldn't have changed much, so warming would continue (for about 100 years until temperatures equilibrated, assuming human civilization was basically destroyed and no more fossil emissions were taking place).

Case example: the Pinatubo explosion (1991) resulted in a bit less than a decade of steady temperatures, as predicted by climate models at the time:

https://pubmed.ncbi.nlm.nih.gov/11976452/

I suppose if we had a Pinatubo every ~5 years for the next 100 years it would result in the lowest plausible warming scenario, without destroying global agriculture.