WHETHER you dismiss much of the debate about the “climate crisis” as scaremongering or as something that worries you, but you feel that you can’t do anything about it, then perhaps you have something to learn from this unique collaboration between an engineer and a theologian. It is a book that combines practical scientific/engineering explanation with a discussion of traditional and Christian virtues.

Between the introduction and the conclusion, there are 14 chapters, which alternate between practical matters: urgency, innovation, restraint, cost, action, leadership, and decisions, and the four cardinal virtues: courage, prudence, temperance, and justice, plus the three Christian virtues: faith, hope, and love. There are also fifty pages of supporting appendices and notes, primarily supporting the odd-numbered chapters on practical matters. In all, about three-quarters of the material concerns practical matters, and the remainder concerns the virtues.

The even-numbered virtue chapters provide plenty to reflect on in terms of how to live a “good” life. They are relatively short and written in a very gentle but persuasive style, and I enjoyed engaging with them. I find myself, however, a little conflicted about the more practical chapters and accompanying appendices.

These practical chapters lay out very clearly the challenge of reducing greenhouse gases to halt the progress of global warming. Their premise is simple: it is no use waiting for new technologies to come along and save the day — the often unstated assumption of politicians and other leaders in industry and elsewhere. Such “convenient solutions” can neither be developed nor deployed in the relatively short period between now and when global warming reaches the point of “no return” in about 2050. If humanity are to avoid this, we collectively have to stop kicking the can down the road and start taking both individual and collective action now — and that’s where the values come in.

Failure to achieve this goal means that increasing areas of the world will become unsuitable for food production, and their populations will migrate to areas where food production is still possible. This will be at a scale that will give political leaders nightmares beyond their wildest imaginings and ultimately lead to global wars between starving migrants and countries trying to hold them back.

To be clear, I am largely in agreement with that premise and predictions, which are well supported by the appendices with their tables and graphs. The “way forward” proposed is that humanity, especially in the developed world, has willingly (with restraint) or unwillingly (with constraint) to eliminate the biggest contributors to greenhouse gasses:

• the use of fossil fuels in boilers for heating and cars, trucks, ships, and planes;
• the production and use of cement;
• the rearing and consumption and use of ruminant animals (cattle and sheep, including dairy products); and
• the cultivation and use of conventionally grown rice; and also
• halve energy use for all purposes.

Now, for me, if one dismisses the idea of technology coming to the rescue, it is a big leap to imagine that wholesale behavioural change is going to happen, especially against a background of increasingly bellicose and extravagant political rhetoric. Yes, an increasing proportion of the population might embrace the cardinal and Christian virtues as a result of recognising their moral responsibilities to the rest of humanity and the planet, or becoming ever more worried by what is happening to the global climate; but will that scratch the surface of the problem? Can you imagine politicians setting out their stall on that basis and hoping to remain in power?

I like the premise of this book: it is a refreshing change of approach, and I would recommend it as an excellent bridge between faith and the science (many of the ideas expressed therein mirror my own in a series of lectures in 2023). Its leap of faith, however, matches a cartoon that I saw years ago, in which a student is explaining his work to his professor on a chalkboard covered in equations which end with “. . . and then a miracle occurs.”

The Revd Dr James Currall is an environmental scientist and retired priest of congregations in Sutherland and Easter Ross, in the Highlands of Scotland.

Promise the Earth: A safe climate in good faith
Julian Allwood and Andrew Davison
Cambridge University Press £15.99
(978-1-009-56399-4)
Church Times Bookshop £14.39