British readers could be forgiven for thinking that 2011 was the "Year Without a Summer", but actually the phrase refers to 1816. In that year, not just Britain but the whole of the Northern Hemisphere was plunged into a kind of apocalyptic nuclear winter. The chief cause was a volcanic eruption a year earlier on the island of Sumbawa in Indonesia... the biggest eruption the planet had seen for more than a thousand years. 80,000 people were killed instantly, and the ash cloud that was blasted into the upper atmosphere blotted out the sun over half the world, causing surface temperatures to plunge to record lows.
Across Europe crops failed, food prices soared and famine was widespread. People took to the streets: there was rioting, arson and wholesale looting. Nowhere was the problem felt more acutely than in Switzerland, where the government was forced to declare a state of emergency. In the area around Lake Geneva it rained almost every day, the Sun was perpetually hidden by clouds, and there was frost even in August. Not a pleasant place at all -- certainly not the sort of place for a wealthy young British aristocrat to suddenly choose to relocate to.
The conditions at the time -- not just the cold and gloom, but also the primitive responses of the population at large -- inspired Byron to write one of his most famous poems, called "Darkness". The poem extrapolates the situation to a time when the Sun itself has grown dark, and people revert to a savage, animal-like existence. As with all poems, "Darkness" can be interpreted in a number of different ways. On the face of it, it's simply an attempt to portray in realistic terms what might happen if such a catastrophe befell the Earth. That's probably the way most people would read it today, and it's certainly the way I viewed it until I read what other people had written about it.
What that straightforward interpretation misses is the fact that in those days most people believed in the literal truth of the Bible, and its predictions about the way the world would end. It was expected that sinners would go to Hell, which is effectively what Byron's poem is describing -- except that in his version, everyone ends up in Hell. There is no salvation for the virtuous. This bleakly pessimistic view (which most people today would consider simple common sense) must have been intensely shocking at the time.
A third interpretation I've come across suggests that the poem wasn't meant to be taken seriously -- that in effect it's a satire on the social situation at the time. By taking current events and exaggerating them, Byron is poking fun at the ignorance of the masses and their mindlessly self-defeating behaviour. Again, to get your head round this, you have to put yourself back in the mind-set of the time at which the poem was written... not an easy thing to do. Whatever Byron's original intention, there's no doubt that the poem set the tone for the gloomy "end-of-the-world" sub-genre of science fiction so beloved of British writers in the later nineteenth and early-to-mid twentieth centuries.
Although it's virtually forgotten as a meteorological phenomenon, the non-summer of 1816 did have a couple of lasting cultural effects. Unable to do anything outdoors, Byron and his house-guests had no alternative but to stay inside and write. Byron, as we have seen, wrote the poem "Darkness". His guest Mary Shelley wrote the original version of Frankenstein. And another guest, John Polidori, wrote a short novel called The Vampyre -- not a well-known work in itself, but culturally significant because it transformed the gawky, red-faced, red-haired, pot-bellied vampire of East European folklore into the cool, sophisticated, aristocratic vampire of modern times... modelled at least in part on Lord Byron himself!