The content of Digital Transformation (DT) as a factor of research library sustainability is discussed. In Part 2, the authors argue that the most significant vectors of digital transformation (DT) in this country are: exponential growth of remote users (readers); development of e-libraries; digital resources and specialized computerized systems; digital user services provided online; personification of library services in the digital environment; library collections digitalization, etc. Eventually, the digital space for collection development, storage and information retrieval emerges. The authors analyze the library digital space, its interior and exterior components. Building open digital information spaces on the basis of libraries induces sustainable development (SD) of residential settlements, attracts users to the libraries, provides specialists with the instrument for advocating and promoting sustainable development goals (SDGs). The authors describe the thematic collections in ecology and nature management acquired by Russian libraries, including RNPLST. They analyze the findings of the ecological movement survey of Russian regional libraries and discuss challenges and concerns related to the libraries digital transformation (LDT). The authors introduce the term (green ICT). They conclude that against the challenges of SDGs and conspicuous doubts of non-achieving these goals, the digital transformation may become a powerful instrument for achieving them. This is also important in the library and information sector. The authors insist that the digital transformations in the libraries support the SD principles.