This paper aims to analyse the implications between the declining and shrinking cities, urban vacant lands, urban land uses, green infrastructures, urban green areas, and their impacts on climate hazard change. The analysis departs from the basic assumption that urban vacant land sites and spaces have a negative connotation, but when supported by the appropriate policies and programmes of incentives, they can turn around and develop the essential green infrastructure to enable the mitigation of climate change hazards, economic growth, and socio-ecological development. The method used is the analytical-descriptive based on the theoretical and empirical literature review. It is concluded that land uses from vacant land to urban green innovation infrastructures and forest areas contribute to mitigating the dangers of climate change, potentially creating green environments in support of human health, individual wellbeing and improved quality of life for residents in the respective community.