Online social media such as the microblog Twitter are key digital arenas shaping the public discourse on important societal topics. Automated social media accounts, so-called “social bots”, have emerged as a controversial phenomenon, proven to both disrupt and support online communications on topics such as political elections and public health. To what extent social bots also impact online conversations on climate change, environmental crises, and sustainability remains unknown however. We present a review of current research on social bots and their potential impact on Twitter discourses around climate, environmental, and sustainability topics; we collect the methods used to detect social bots, approaches to determine their online impact, extract a high-level normative assessment of automation, and summarize the recommendations for stakeholders to manage the challenges created by automation. We note a lack of common, comparable methodologies to robustly assess the impacts of social bots, which contributes to simplistic causal claims about their impact on public opinion and behavior. We identify research needs and offer methodological recommendations for future research on this topic of growing importance.