A day off to save the planet? Here’s what a four-day week could mean for UK carbon emissions

The benefits of shorter working hours to worker wellbeing have led to a groundswell of support for a four-day working week in the UK, culminating in high-level political endorsements and ground-breaking pilot programmes. Yet, the environmental impacts of working time reduction remain unclear.

To understand the potential impact of switching to a four-day week on carbon emissions, I interviewed 24 people from 18 organisations, representing a range of industries, that participated in the UK’s largest four-day week trial to date in June to December 2022. 

My results revealed that switching to a four-day week with no loss of pay would only reduce emissions if people dedicated their newfound leisure time to low-carbon activities—otherwise there’s a risk of pushing up carbon footprints from extra shopping and travel. On the other hand, given the freedom to choose, many workers would happily take a slightly lower salary in return for an extra day off, which would almost certainly cut emissions.

There are two main channels that shape the relationship between working hours and emissions: the first is the link between working hours and income (i.e. the size of your paycheck), and the second is the link between working hours and and how people spend that income (i.e. the percentage breakdown of your spending).

• First, with regards to income, our personal carbon footprint, on average, increases as our income grows, which means that choosing to work a four-day week with a lower salary could cut emissions. This is great when people want to make this trade-off, but taking a pay cut is untenable for many workers, especially in the current cost of living crisis.

  To make a four-day week possible without sacrificing workers’ incomes, businesses must create the same amount of value in four days as they previously did in five, which requires a huge jump in productivity (measured per person-hour). Happily, this is exactly what happened during trials of the four-day system - more on this below. 

• Second, switching to a four-day week will change how people spend their income, which affects emissions. For example, even with no change to their salaries, people may rearrange their budgets (e.g. spending less on commuting but more on long weekend holidays), clearly affecting their carbon footprints.

Using productivity gains to reduce working time, rather than boosting economic growth, is quite a radical idea in modern society. Think of it like this: when new technology is adopted that boosts per-hour productivity (hello AI!), we can choose one of two options – produce more stuff while keeping the same working hours, or produce the same amount but in fewer hours. Choosing the former leads to economic growth – increased output, incomes, profits, and consumption – whereas choosing the latter holds these stable while reducing emissions and working hours. 

The factors that influence this choice differ from country to country, and even from person to person. It is, however, a live debate in much of the world, as it cuts to the core question of what we as a society hold to be most valuable. 

In recent decades, the UK has consistently favoured growth over leisure in this trade-off, which explains why we work just 10% fewer hours than 50 years ago despite productivity more than doubling in that time. This doesn’t seem likely to change any time soon given new chancellor of the exchequer Rachel Reeves’ laser focus on economic growth. The trade-off between growth and leisure time can be sidestepped, however, when reduced hours generate additional productivity growth, as discussed further below.

Would you take a pay cut to get an extra day off? Eleven of twelve workers interviewed said that they would have accepted a lower salary in return for a four-day week, such is their appreciation of their newfound leisure time. 
 

In the words of one worker: “What I’ve come to realise is that time is the real most valuable thing that you can have.”

In reality though, these workers didn’t need to, as their workplaces implemented the four-day week with no loss of pay. 

To make this possible, workplaces embarked on productivity blitzes. Organisations cut the frequency and length of meetings, reduced email checking, and rearranged schedules. On top of this, the very fact of having less time to complete tasks, coupled with a longer weekend to decompress, made work time more productive. 
 

As one manager put it, “It’s amazing how quickly things can get done whenever time is limited”. 

Add to this employees’ enhanced motivation and mental health, and we begin to understand how these organisations were able to supercharge productivity.

As a result, output and revenue either remained stable or increased in every single organisation, despite working 20% fewer hours. In one case, a manufacturing business saw total output grow by 40% after making the switch.

This allows people to enjoy shorter hours without sacrificing their purchasing power. However, since production and salaries remain stable, there is no effect on emissions via changes to income.

If you had an extra day off, how would you use it? And would you spend your money differently? As it turns out, answers to these questions vary a lot.

While workers’ total spending generally did not change, moving to the four-day week triggered a rearrangement of their budgets.

• About a quarter of people began to take a slower, more deliberate approach to their leisure time.  These people felt that a four-day week removed the need to “blow off steam” over the weekend, and hence ended up spending less on nights out and drinking. Overall though, socialising and going out was the most common thing that workers spent more on.
   
• The four-day week allowed people to save money on things like groceries and commuting. Groceries was the most commonly reported item that workers spend less on under a four-day week, with a quarter of interviewees giving this answer. This was not, however, because they bought less food, but because their extra day off allowed them to shop more economically. Workers then used these savings to expand their consumption of other goods.

Leisure travel was the number two item that people spent more on under a four-day week. 

Domestic intercity trips to visit family and friends, as well as weekend jaunts to Europe, become more worthwhile with a three-day weekend.

Not all of this travel was by plane, however. Only two out of twelve workers reported that they fly more often under a four-day week; the more common effect was an increase in overland travel.

All in all, these budget rearrangements suggest a slight increase in carbon footprints under the four-day week. This is because much of the observed reductions in spending came from people purchasing goods at a discount, whereas increases in spending were due to consuming additional goods and services, some of which, like air travel, are quite carbon-intensive.

An overwhelming takeaway from interviews was that the four-day week with no loss of pay has proven hugely beneficial to workers’ wellbeing. Regardless of the impact on emissions, most people would agree that this is reason enough to support the idea. In situations where productivity can grow quickly enough to support a shift to four days with no loss of pay, who’s to say people should continue to toil for five?

But beyond the four-day week with no loss of pay, there are other ways we could work less and reap a double benefit of reduced emissions and better wellbeing.

Policy could make it as easy as possible for overemployed workers to request part-time schedules. 

• More flexible employment terms or the option to request shorter hours in lieu of a raise, like in Austria, would be great starts. Wage freezes, instead of reductions, could also be used to implement shorter working hours by borrowing against future productivity growth.

  These policies also ensure that all workers have the choice to shorten their hours, not just those in the select industries where short-term productivity growth is high enough to implement the four-day week with no loss of pay overnight. Given the near-unanimous willingness of interviewees to trade off their income for leisure time, these could be extremely popular policies.

• Programmes to support reduced hours with no loss of pay on the condition that the time off is spent on some low-carbon activity, like parenting, further education, or volunteering, could also reduce emissions while enhancing wellbeing. They would be easy to implement: a similar scheme to support youth activities already exists in Switzerland.

These options suggest that working time reduction presents a range of low-hanging win-wins for people and climate. 

At the end of the day, the prime objective of economic policy should be to improve people’s well-being. If we can achieve that while reducing emissions, why not get to work?

Want to learn more? Read the full dissertation: 'Working 9 to 5, what a way to keep emitting? Impacts of a four-day working week on carbon emissions in the UK'.