GEOLOGISTS are still arguing over the start date of the so-called Anthropocene epoch. That’s perfectly understandable, since the term refers to an age defined by consequential human impact on earth’s geology and ecosystems. Some argue it began millennia ago with the onset of agriculture; some say the Industrial Revolution; modern day thinkers reckon the onset of “the great acceleration” following the Second World War is the true marker. The bottom line, in a world where damage to the planet is a daily concern, is that the Anthropocene is with us now – and so is a brand new opera bearing the same name by the Scots-based composer-librettist team of Stuart MacRae and novelist Louise Welsh, commissioned by Scottish Opera and fast approaching its premiere on 24 January at Glasgow’s Theatre Royal.