  The scientific data about the state of our planet, presented at the 2012
(Rio+20) summit, documented that today's human family lives even less
sustainably than it did in 1992. The data indicate furthermore that the
environmental impacts from our current economic activities are so large, that
we are approaching situations where potentially controllable regional problems
can easily lead to uncontrollable global disasters.
  Assuming that (1) the majority of the human family, once adequately informed,
wants to achieve a "sustainable way of life" and (2) that the "development
towards sustainability" roadmap will be based on scientific principles, one
must begin with unambiguous and quantifiable definitions of these goals. As
will be demonstrated, the well known scientific method to define abstract and
complex issues by their negation, satisfies these requirements. Following this
new approach, it also becomes possible to decide if proposed and actual
policies changes will make our way of life less unsustainable, and thus move us
potentially into the direction of sustainability. Furthermore, if potentially
dangerous tipping points are to be avoided, the transition roadmap must include
some minimal speed requirements. Combining the negation method and the time
evolution of that remaining natural capital in different domains, the
transition speed for a "development towards sustainability" can be quantified
at local, regional and global scales.
  The presented ideas allow us to measure the rate of natural capital depletion
and the rate of restoration that will be required if humanity is to avoid
reaching a sustainable future by a collapse transition.
