To avoid catastrophic changes in Earth systems that will seriously reduce the livability of our planet, we urgently need to change the way we produce and consume, reducing both the extraction of resources from and emissions to the environment. The sustainability of consumption patterns depends on motivation, ability, and opportunity to choose sustainable alternatives. Available opportunities depend on supply and socio-technical systems, which often make it difficult to choose more sustainable alternatives. The societal context also influences consumption needs and norms, and more sustainable alternatives tend to be less salient and more costly in time, effort, and money, which reduces the likelihood that pro-environmental intentions are formed and implemented. Limited cognitive and other resources (i.e., ability) is another important source of inconsistencies between pro-environmental values, attitudes, or intentions and behaviour. Sustainable consumer behaviour is often expensive, which can make it out of reach for people on a tight budget, and many people do not understand the negative environmental side-effects of their behaviour. Habituation is a practical necessity to cope with everyday demands and goal-striving. However, in a time where many aspects of existing lifestyles are challenged, existing unsustainable habits create serious barriers to make consumption patterns more sustainable. Voluntary changes of unsustainable consumption patterns require that consumers are motivated to consider alternative options and make a deliberate decision to try something new and sustainable. Governments promoting, facilitating, and sometimes even forcing the necessary changes should focus on behaviour changes with the biggest impacts as identified by research.