Traditional approaches to sustainability are rooted in behaviour change, but could this actually slow progress? Peter Harper and Stuart Reynolds, External Lecturers in Natural Sciences at the University of Bath, suggest policymakers should prioritise what works at scale, even when it challenges familiar narratives.
Debates on sustainability tend to focus on two closely linked challenges: climate change and biodiversity loss. Both are urgent, well-evidenced and interdependent—climate change will damage ecosystems, while changes to nature, such as those driven by modern farming, will affect the climate. Progress on one is therefore unlikely without progress on the other.
There is broad agreement in policy circles about the scale of these challenges. If continued, either could seriously disrupt global stability and modern economic systems. But progress is held back by both behaviour and institutional inertia, as well as less visible divisions – or “fault-lines” as we like to call them – within the sustainability debate itself.
These fault lines reflect a tension between approaches that feel intuitively correct and those that are guided by data or systems-level thinking. The former are often more appealing to the public, but the evidence does not always support them. This can hinder the development of unified policy responses and raises a difficult question: could some widely supported approaches actually be slowing progress towards sustainability?
Sharing versus sparing
A clear example of the tensions that exist between traditional sustainability thinking and emerging alternatives lies in farming. A long-standing debate asks whether biodiversity is best protected by combining food production with natural habitats (sharing land) or by producing food more intensely in some areas to free up land for habitat restoration (sparing land).
Organic and low-impact farming approaches, widely supported within the sustainability discourse, tend to favour sharing. But integrating food production with natural habitats leads to lower yields and means that more land is needed overall, potentially limiting space for wildlife.
In contrast, evidence suggests that intensifying production in some areas to release unused or spared land for natural habitats can, in many contexts, deliver better biodiversity outcomes.
Livestock sits at the centre of this debate. Animal farming uses the majority of agricultural land, either for grazing animals or growing their feed, yet it provides a relatively small portion of the calories people consume worldwide. Evidence is clear that the total biomass of farmed animals is far greater than that of wild mammals. Moving towards more crop-based farming could cut land use and emissions significantly, which may help to reduce the trade-off between sharing and sparing natural habitats. Even so, the topic remains political and socially contentious.
Alternative proteins
Reducing livestock production raises a practical question: what can people eat instead?
The building blocks of protein, called amino-acids, are found in many crops and can be produced using roughly a tenth of the land and emissions compared with animals sources. While plant proteins sometimes need to be combined with other foods, such as rice and dhal, to match the quality of animal protein, this is already common in many diets.
Turning crops into meat alternatives often involves a lot of processing, which has led to concerns about classing them as ultra-processed foods (UPFs) and creates a perceived trade-off between health and sustainability. Yet this distinction may be overstated. Diets in many high-income countries already rely heavily on processed foods. In this context, there is little overall health loss in embracing the livestock alternatives—it is unlikely that alternative proteins represent a deterioration in diet quality and may even offer improvements.
Decarbonisation versus negative emissions
Decarbonisation has been the central strategy for addressing climate change—and has delivered significant progress. UK carbon emissions, for example, have fallen substantially since 1990, to around half of what they were. But further reductions are likely to be more difficult. Remaining emissions include hard-to-abate sectors and, so far, emissions embodied in imports have not been taken into account. Consumption-based emissions also remain high.
In addition, meeting climate targets must require not only reducing emissions but actively removing greenhouse gases from the atmosphere. This implies a growing role for negative emissions technologies (such as reforestation) and other forms of direct cooling (such as the injection of aerosols into the stratosphere). These approaches are often viewed as secondary or controversial, however current trajectories suggest they are necessary alongside continued decarbonisation.
Lifestyle change versus system change
Another persistent debate in the sustainability discourse concerns the relative importance of individual behaviour change versus systemic, technology-led solutions.
Lifestyle changes can reduce emissions, but uptake remains limited. By contrast, system-level changes can deliver large-scale reductions with minimal disruption to daily life. For example, decarbonising the electricity network or reformulating food products.
These approaches are sometimes criticised for allowing existing consumption patterns to continue. But their scalability and speed may make them indispensable in the near term.
Implications for policy
Sustainability policy is often shaped by values as well as evidence. While this is unavoidable, it can lead to a preference for solutions that feel more societally acceptable rather than those most likely to succeed.
Across the examples outlined above, a common theme emerges: approaches that align with intuitive preferences are not always those best supported by evidence.
This does not negate the importance of public engagement and behavioural change, which have long been at the core of traditional green discourse. But relying on these alone is unlikely to deliver the pace of transition required. Recognising and addressing tensions is essential. In some cases, more technical, less visible interventions may offer greater potential for rapid and large-scale impact.
The challenge for policymakers is not only to identify what works, but also to build the institutional and public support needed to implement it. A pragmatic approach may involve prioritising interventions that are effective at scale, even where they challenge established narratives within sustainability debates. In practice, this may mean giving greater weight to technical or system-level interventions, and remaining open to approaches that may initially appear counterintuitive.
All articles posted on this blog give the views of the author(s), and not the position of the IPR, nor of the University of Bath.
