The paper presents the experience of the Department of Foreign Languages, Ecological Faculty, RUDN University, in teaching English for specific purposes (ESP). A case study of the introduction of 'An Ecomodernist Manifesto' in ESP classes is discussed in the article. 'An Ecomodernist Manifesto' is a 25-page essay written by 18 environmental scientists, activists and scholars. The present study is an attempt to consider the value of the manifesto for teaching English to upper-intermediate and advanced students of environmental studies faculties. It is found that the manifesto can serve this purpose in terms of its content and language. Implementation of the manifesto in ESP courses has positive aspects as well as challenges outlined in the conclusion. Taking into account the obtained results, the manifesto can be recommended for students with upper-intermediate and advanced levels of language proficiency. This study might be interesting for teachers of foreign languages and contribute to the field of didactics.