Social-media data for urban sustainability

A voluminous and complex amount of information - 'big data' - from social media such as Twitter and Flickr is now ubiquitous and of increasing interest to researchers studying human behaviour in cities. Yet the value of social-media data (SMD) for urban-sustainability research is still poorly understood. Here, we discuss key opportunities and challenges for the use of SMD by sustainability scholars in the natural and social sciences as well as by practitioners making daily decisions about urban systems. Evidence suggests that the vast scale and near-real-time observation are unique advantages of SMD and that solutions to most SMD challenges already exist.