From the Wikipedia:
"The Natural Step is a non-profit, non-governmental organisation founded in Sweden in 1989 by scientist Karl-Henrik Robèrt and The Natural Step is also used when referring to the partially open source framework it developed. Following publication of the Brundtland Report in 1987, Robèrt developed The Natural Step framework, setting out the system conditions for the sustainability of human activities on Earth; Robèrt's four system conditions are derived from a scientific understanding of universal laws and the aspects of our socio-ecological system, including the laws of gravity, the laws of thermodynamics and a multitude of social studies. The Natural Step has pioneered a "Backcasting from Principles" approach meant to advance society towards greater sustainability.
Whole-systems thinking and backcasting from sustainability principles form the basis for numerous applications and tools to plan and (re-)design organisational strategy, organisational processes, product/service innovation and business models. Its biggest advantage is the concept of 'simplification without reduction' to prevent getting lost in the details with the complex topic of sustainability. For almost 30 years, the approach has been implemented, proven and refined in education, research, businesses, municipalities, regional and national governments, inter-governmental organisations (e.g. UN, EU) and a multitude of NGOs around the world.
Currently, The Natural Step has offices in 11 countries and numerous associates and ambassadors in more than 50 countries. Next to the Five Level Framework and the TNS Framework (or Framework for Strategic Sustainable Development), the TNS 'theory of change' shows an integrated cascaded approach to accelerate change towards a sustainable society by collaboration on individual, organisational and multi-stakeholder system level. Change programs and transition Labs include Futurefitbusiness.org and the Alberta, Canada energyfutureslab." (https://en.wikipedia.org/wiki/The_Natural_Step)