Here's a cheerful thought: An eruption from a supervolcano can kill us all; the event being as potentially destructive as solar storms and an asteroid hitting the earth. (See this article for a summary of how the world could end).
The Atlantic recently ran an article on an alternative to the asteroid theory of dinosaur extinction, generally considered to be the fifth mass extinction. This competing theory is - volcanoes. A series of volcanic eruptions originating from a part of what is now western India known as Deccan Traps, argues a Princeton geologist, gradually made the environment untenable for these megafauna. (Her website and explanations are here).
The dinosaurs is generally considered to be the fifth mass extinction (and some writers argue that we are currently living through the sixth) so, there is particular urgency in understanding these events in order to prevent our own. It's interesting that in the asteroid vs volcano debate on how the dinosaurs died, volcanoes are making a comeback now after the asteroid interpretation have been generally accepted as scientific fact. The visibility and scale of volcanic activity recently might have played a part; according a volcanologist, we learn by living through it, which is not particularly comforting.
On a more positive note, simulating volcanic winters by injecting sulphur particles into the atmosphere has been mooted as a possible way of combatting global warming. We still need to know more about not just the science but also the human response and how societies historically organized itself around these challenges in order to assess how different communities around the world could potentially react to such events in the future - real or simulated.
Am reading about and will be writing a post later on volcanic winters in recent environmental history research - more soon!