BACKGROUND The world has experienced devastating extreme weather events, alongside slow-onset processes including increasing temperature means, that scientists agree are manifestations of human-induced climate change. Even with radical action to reduce greenhouse gas emissions, effects of climate change will become increasingly severe.

OBJECTIVES The aim of this review was to classify impacts of climate change for people who use alcohol and other drugs (AoD), as reflected in peer reviewed literature.

METHOD A scoping review was conducted to achieve this. Included studies involved a human population, a climate change related exposure, and an AoD outcome. Studies were published in English between 1998 and November 2023. Exposure events of interest included extreme heat, fires, storms, floods, droughts, and longer-term environmental changes. 8,204 studies were screened, with 82 included for data extraction and narrative analysis.

RESULTS Most papers describe increased AoD use, with smaller numbers showing decreased or unchanged substance use. Some studies identify unplanned withdrawal, changed drug markets, disrupted service access, specific physiological vulnerabilities of AoD users to extreme heat, and compounding effects on mental health. We note the relative absence of peer reviewed studies investigating impacts of climate change on AoD use in low-and middle-income countries. Further, few studies consider impacts that occur because of long-term or gradual climatic shifts such as environmental changes that are detrimental to livelihoods.

CONCLUSION It is crucial to document effects of a changing climate on people who use AoD so that policy and services can meet future needs. We call for research to remedy gaps identified in this review.