The challenge of uncertainty: can sustainability be achieved under unpredictable ecological dynamics?

<title>Abstract</title> Unpredictable environmental dynamics may be the greatest challenge of our time^1,2. However, sustainability initiatives are designed with the assumption that people’s access to natural resources is relatively predictable³. This assumption is based on the principle that to use resources sustainably users must have the ability to exclude free riders through clear boundaries4. A lack of boundaries is linked to open access and the tragedy of the commons5. However, clear and enforceable boundaries are not always possible, especially in areas with unpredictable natural resource dynamics^6,7. How sustainability can be achieved in unpredictable systems is still poorly explored8. Here we show that many socio-ecological systems have developed customary systems to deal with unpredictability and achieve sustainability. We found that predictability levels below 50% lead socio-ecological systems to display broad reciprocal access across socially and spatially fuzzy boundaries and high levels of mobility. Our results demonstrate that functioning governance structures do not occur only when people have predictable access to resources and clear boundaries to resource extraction are imposed. We show that to deal with the increasing level of unpredictability around the world9, sustainability science and practice must recognise the possibility of governance structures based on mobility and information/resource sharing⁶.