There is a kind of climate change, though, that would be far more immediate in its impact. Abrupt climate change (Wikipedia entry here) is a sudden increase of anywhere from 2C to, perhaps, 10C of warming – that’s 3F to 16F – in about one to three years. Even at the low end, abrupt climate change would disrupt rainfall and change temperatures so much that getting the harvest in at today’s levels would be impossible, and widespread starvation would be almost impossible to avoid. Wars and more or less widespread breakdowns of order would probably ensue. At the higher end of the scale, the impact would be many times worse.

Unfortunately, ice core records seem to show abrupt climate changes of about 4C to 10C occurring about 11,000 and 22,000 years ago. The reason for the warming is disputed, and may have to do with the sudden release into the environment of CO2 and methane that had previously stored in permafrost. The idea is that gradual warming caused this stored carbon to quickly erupt in a kind of chain reaction of warming that was local at first, quickly becoming global.

We have a potential “time bomb” of this type today in the yedoma, a region of permafrost that has huge amounts of carbon stored in it, and that may not be as “perma” as we hope . Another candidate is a sudden “burp” of carbon stored deep in seawater. or of methane clathrates that are currently frozen under frigid waters.

We know that the previous abrupt climate change events occurred even without the human-caused pressure of greenhouse gas emissions that’s the main cause of the warming we’re seeing today. So, with rapid warming already underway, abrupt climate change now should be urgently studied. This research would probably tell us a lot about today’s ongoing climate change, and the odds that it might be runaway – even if not actually abrupt – as well.

Abrupt climate change, though, is what’s called a HILF – a high-impact, low-frequency event, also called a “black swan“. The 9/11 terrorist attacks of 2001 were a HILF, as was the 2008 financial crisis. HILFs, almost by definition, tend not to get much attention until they actually occur.

With even the most seemingly clear conclusions of climate science being disputed, though – at least in the US – it seems highly unlikely that the study and preparations that would do so much to help will be undertaken until after it’s too late.