1 Department of Geography, Planning and Environment and Loyola Sustainability Research Centre (LSRC), Concordia University, Montreal, QC, Canada.
2 Department of Geography, Planning and Environment and Loyola Sustainability Research Centre (LSRC), Concordia University, Montreal, QC, Canada. jochen.jaeger@concordia.ca.

Rapid increases in urban sprawl in many cities across the planet pose a challenge that needs to be addressed urgently. This study proposes targets, limits, and warning values to urban sprawl as a quantitative reference framework for exploring potential future pathways and to provide guidance for future land management. The reference framework serves to evaluate the effectiveness of potential urban growth management strategies and to assess a set of greenbelt scenarios as potential strategies to mitigate urban sprawl. Using Montreal as a case study, seven urban development scenarios until 2070 are compared, of which only one is assessed as sustainable. Valuable natural and semi-natural areas and agricultural lands surrounding the city provide an opportunity to establish a greenbelt. As an example of a growth management strategy, we evaluate four greenbelt scenarios regarding their potential to reach the proposed targets and limits. At Montreal's broader city scale (Census Metropolitan Area, CMA), the results reveal that the greenbelt scenarios would significantly reduce sprawl compared to current trends. However, they would remain insufficient to achieve the proposed target and limit to urban sprawl for Montreal. At the level of municipalities (census subdivisions, CSDs), the greenbelt scenarios would significantly benefit some of them, with one CSD projected to meet its target, while urban sprawl in several others would fall within the range between their limits and warning values. The findings demonstrate the use of targets and limits to serve as benchmarks in land-use management. The results reveal a high potential of greenbelts to positively influence urban development towards sustainability, even if the greenbelt proposals currently under discussion would not achieve the recommended targets and limits corresponding to sustainability.