Beyond Ownership: Sufficiency and inequality shape product-sharing’s sustainability potential
This study reveals that product-sharing systems in Japan only yield environmental benefits when higher-income groups adopt sufficiency-driven consumption habits, as infrastructure alone cannot overcome the rising relative costs of access-based models and a trilemma exists between environmental gains, energy access, and welfare equity.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
We live in a world where owning things feels like a default setting. We buy the latest phone, the newest car, and the most efficient appliance, often replacing them long before they break. This culture of ownership drives up the use of raw materials, creates mountains of waste, and pumps carbon dioxide into the atmosphere. In response, many experts have championed a different approach: the circular economy. The idea is to keep products in use for as long as possible, either by sharing them or by simply needing fewer of them. This shift moves us from owning a physical object to accessing a service, like renting a car instead of buying one, or borrowing a drill instead of buying a new one for a single job. The hope is that by sharing, we can reduce the total number of items we need to make, thereby saving resources and protecting the climate.
However, simply changing how we access goods does not automatically fix the problem. A new study suggests that the environmental success of these sharing models depends entirely on who is doing the sharing and why. If the people who consume the most stop buying things and start sharing, the planet benefits. But if the people who already have less are forced to share because they cannot afford to own, or if the wealthy continue to buy while the poor share, the environmental gains can vanish or even turn into losses. The research, focused on Japan, reveals a complex trade-off: we cannot easily achieve environmental protection, fair access to services, and equal well-being for everyone all at once.
The researchers built a sophisticated computer simulation to explore these dynamics, focusing on the Japanese economy. They did not just look at prices or technology; they modeled how different types of people actually behave. They divided households into three groups based on their income and their mindset: those with high incomes who are motivated by environmental concerns, those with medium incomes who are somewhat cautious, and those with low incomes who are primarily driven by the need to save money. The study then tested twelve different scenarios. In some, the wealthy were encouraged to share and buy less because they cared about the planet. In others, the poor were encouraged to share because they could not afford to own. They also varied the quality of the infrastructure, such as the availability of car-sharing stations or digital platforms, to see if better access would change behavior.
The results challenged a common assumption: that making sharing easier will automatically lead to a greener world. The study found that better infrastructure alone does not shift people away from ownership. In fact, as wages rise over time, the cost of hiring a service (which requires paying workers) becomes more expensive relative to owning a product and doing the work yourself. Because of this, better infrastructure often just amplifies existing habits. If a group of people is already inclined to own things, better access to sharing services might not change their minds. Conversely, if a group is already trying to share, better infrastructure helps them do it more, but it does not force a reluctant group to change.
The most critical finding concerns who reduces their consumption. The simulation showed that environmental footprints drop significantly only when higher-income groups reduce their ownership of energy-using goods, such as cars and appliances, and adopt a lifestyle of "sufficiency"—meaning they simply need less. When these wealthier households buy fewer new items, the total amount of waste and carbon emissions falls. However, when lower-income groups are the ones reducing consumption, the environmental benefits are minimal or non-existent. This is because lower-income households already spend a large portion of their budget on basic energy use, like heating and electricity, which is not affected by whether they own or share a specific appliance. Furthermore, if lower-income groups are forced to share because they cannot afford to own, they may end up spending money on services that take away from their ability to buy other essential goods, hurting their overall well-being.
The study also uncovered a difficult dilemma, or a "trilemma," where three desirable goals cannot be achieved simultaneously. The first goal is environmental benefit, the second is equal access to energy services for everyone, and the third is fair economic welfare. The simulations showed that you can have environmental benefits and fair access, but only if the wealthy reduce their consumption, which widens the gap in overall well-being between the rich and the poor. Alternatively, you can have fair well-being and equal access, but this often requires lower-income groups to shift to sharing models, which can actually increase total environmental footprints because the wealthy continue to consume heavily. In short, the path to a sustainable future is not a straight line where everyone shares more and the planet heals. Instead, it requires specific changes in the behavior of the highest consumers.
The researchers emphasize that policies promoting sharing must be careful. Simply building more sharing stations or creating apps for renting items will not solve the problem if the relative cost of these services remains high compared to ownership. In fact, without addressing the underlying costs, better infrastructure might just make it easier for the wealthy to maintain their current consumption habits while the poor struggle to adapt. The study suggests that for sharing to be truly sustainable, it must be paired with measures that specifically encourage the wealthy to consume less, rather than just hoping that access-based models will naturally lead to a reduction in resource use. The path forward requires understanding that not all forms of sharing are equal, and that the environmental impact depends less on the model of ownership and more on the lifestyle and economic reality of the people participating in it.
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