In the Guardian’s New Zealand edition, Perpetual Guardian CEO Andrew Barnes makes the case for the environmental benefits of the 4-day week:

If we want to relieve the strain of a globally growing – and commuting – population, we need to rethink how and where we work. Working more flexibly – both in timing and location – could have a massive impact on transportation and electricity production, two of the main contributors to greenhouse gas emissions.

How does it work? Organisations adopt a four-day working week, the daily head count in the office drops by approximately 20% and the number of cars on the road drops by at least a fifth. It’s a win-win-win scenario for employees, employers and the environment….

The intensity of congestion and the lengthening of commutes are a byproduct of the way we work today, with billions of hours, dollars, fuel gallons and pounds of carbon dioxide expended each year in developed countries, where the term “rush hour” has been part of the lexicon for as long as anyone can remember. Even if we leave aside the climate change question and apply a pure economic lens, a widespread model of working which prioritises productivity and efficiency over a robotic adherence to working hours (which were once dictated by the sun and are now mostly arbitrary) is a no-brainer.

When we turn our minds to the welfare of the planet, the answer is just as obvious. The human resources department of UC Davis in 2018 bluntly made the environmental case for work flexibility: “Not going into work could be one of the most environmentally sustainable things you can do as an individual employee.”… Changing to a four-day working week won’t by itself solve the climate crisis, but combining it with other progressive policies will be part of the global climate mobilisation we indisputably need.

When I was writing SHORTER (US|UK), I reviewed the literature on the environmental benefits of shortening working hours. Overall, it struck me that the picture was positive– obviously there are energy and carbon savings when people have to drive fewer days or fewer miles, and companies can turn off the lights for another day– but some of the studies also calculated their impacts based on an assumption that a shorter workweek translated into lower salaries and less consumption.

It’s not quite as as clear what happens when you reduce working hours but salaries stay the same; the Microsoft Japan summer experiment was quite promising, but is still only a single study. Nonetheless, I think Andrew’s quite right, and we should factor in the environmental benefits of shorter working hours in policy debates about the future of work.