Nachhaltigkeit ist ein Fremdwort, writes Silvia Schaub in her article in Schweiz am Sonntag at the weekend.* 'Sustainability is a foreign word'. In German, Sustainability is a word taken from another language. A foreign concept, rendered into German by using the existing building blocks: nachhaltig, 'sustained, lasting, persistent' and keit, a suffix like the English -ness to turn it into a noun expressing the concept of being sustained or lasting.
It's clunky but functional - not unlike our English Sustainability. It's a construction; a concept that we're learning to live by because, as Silvia writes, it's better than the alternatives.
*'Ende der Monokultur - Zeitenwende im Garten', Schweiz am Sonntag, 9.März, pp. 50 - 51.