International investment agreements define commitments on investment protection, but also shed light on how these commitments are to be integrated with other public policy objectives. Investment protection in the context of environmental regulation has been a frequent source of controversy and investor-state disputes. In order to enhance the factual basis for debate in this policy area, the present survey establishes a statistical portrait of governments’ investment treaty writing practices in relation to environmental concerns in a sample of 1,623 IIAs, roughly half of the global investment treaty population. The survey provides a statistical portrait of the extent, kind and frequency of treaty language referring to environmental concerns and the evolution of the use of such language over time. It shows that: i) over time, more treaties contain such language; ii) only about 8% of the sample treaties include references to environmental concerns; and iii) there are wide variations in the content of such language, both across countries and across time.