A third edition was beginning to look improbable. Despite – or perhaps because of – the speed with which large sections of the second edition were drifting into obsolescence, the original sole author increasingly felt that wholesale revision was a bridge too far. But an email out of the blue from JG, proposing a collaborative effort, has made the bridge crossable and enabled the current volume to see the light of day. While we have each led the writing on different chapters, the finished version is a shared endeavour for which we take joint responsibility.

The preface to the second edition talks about the accelerating pace of change in environmental thinking and policymaking, and the steadily rising prominence of environmental issues in public debate. Both trends have since accelerated further, not least with the widespread recognition of the existential threat posed by climate change and the dawn of the Anthropocene, an era shaped by human choices and actions. It would have been challenging enough to write a book amid the ferment of debate surrounding these ‘terrible twins’. But the fog of uncertainty has only been thickened by three game-changing events. Brexit was the first of these; the departure of the UK from the EU in January 2020 is rewriting the rules of the game in ways that remain hard to predict. The second was the Covid-19 pandemic which led to tragic loss of life, lockdowns around the world, profound economic shocks and a short-lived so-called Anthropause in human impacts on the environment. A third shock to the system came in February 2022 with Russia’s invasion of Ukraine, triggering a cascade of geopolitical recalibrations, not least concerning energy. The intertwined and far-reaching implications of these epoch-defining developments make the world an even more unpredictable place than hitherto, and all the while Scotland’s future within or outwith the UK remains hotly contested.