While the development economics paradigm known as sustainable development has been with us for merely a generation or so, the adjective sustainable goes back to 1611, according to OED. A derivative of that adjective, the noun sustainability, came into use much more recently, which may explain the name attached to the paradigm:
1980 Jrnl. Royal Soc. Arts July 495/2 Sustainability in the management of both individual wild species and ecosystems is critical to human welfare.
We cannot help but agree with the application in that reference.