This suddenly fashionable term, a shortening of climate fiction, is obviously based on sci-fi, an abbreviation for science fiction or SF.
Climate fiction is fundamentally dystopian. Its focus is the effect of climate change on human life, perhaps including its continuing existence. Most commentators list J G Ballard’s The Drowned World of 1962 as an early example, a prophetic tale in which melting ice-caps and rising sea levels led to the destruction of civilisation, though the cause was solar flares, not human-derived changes to the climate. In the past decade it has become a frequent theme in SF. Examples are Kim Stanley Robinson’s Science in the Capitol trilogy that began with Forty Signs of Rain in 2004, and The Windup Girl by Paolo Bacigalupi in 2009.
The journalist Dan Bloom claims to have invented the term cli-fi in 2007. It appeared in a Wired article by Scott Thill in December 2010 and Margaret Atwood was another early user, in a Twitter message the following year. This helped to bring the word, and the genre, to much wider public attention (to the extent that an article in the Irish Times in December 2012 mistakenly said Atwood had invented it).
One interesting consequence of heightened awareness of the possible consequences of human influence on the planet is that the genre has begun to move from SF towards the literary mainstream — for example, Margaret Atwood’s The Year of the Flood in 2009; Ian McEwan’s Solar of 2010; and Barbara Kingsolver’s Flight Behaviour, which was shortlisted for the 2013 Women’s Prize for Fiction. An article in the Christian Science Monitor on 26 April was headlined, “Don’t call it ‘science fiction’. Cli-fi is literary fiction.” Some commentators have tried to remove any taint of SF associations from such works by arguing that mainstream cli-fi works are set in the present day or the near future rather than looking speculatively at longer-term implications.