Timescales: Brexit and the climate

I once read a chapter in a book about the nuclear industry which recounted debates related to the burying of nuclear waste in the Nevada desert. Given that depleted uranium has a half-life of 4.468 billion years, how can our civilisation signal to who or whatever inhabits our planet so far in the future that they must not dig too deep at certain locations? What symbols might represent danger for all conceivable life-forms?

I’ve been thinking about timescales, partly in relation to the above table presented by the physicist Jay Lemke in an equally head-spinning paper called ‘Across the scales of time‘. I came across it on a course I’m doing called, appropriately enough, Language and Power. It relates to educational processes but can easily be adapted to other contexts. Here, for example, is a timescale of my own invention:

Jem Finer, formerly of The Pogues, has created a composition called ‘Longplayer’, which you can listen to here. You’re unlikely to get through the whole thing, as it’s 1,000 years in duration. In the meantime, you can also read a series of reflections in the form of exchanges of letters which ponder some of the cosmological and personal conundrums the piece evokes. Here’s one from the comedian Stewart Lee.
The Nobel Prize-winning economist Elinor Ostrom drew on the ancestral wisdom of the Iroquois people in formulating her theses about sustainability. She urged humanity to always think seven generations into the future (around 150 years) when formulating policies.
The British Meterological Office has warned that the target set by the Paris Agreement of restricting a rise in global temperatures to 1.5C could be breached within five years.
Container ships setting off now from the UK which will not reach their destinations for at least 50 days may find that the goods they’re transporting may face an as-yet unknown tariff regime when they arrive, meaning they may never be unloaded.
The Labour leadership has submitted a letter to the Government in which it details its preferences for what sort of arrangements it would like the UK to try to reach with the EU if it should ever come to pass that Britain should one day consider exiting the European Union. The Guardian article reporting on this omits to mention whether the letter was sent by first or second class post.
The kettle is boiling.