Noting the difference between deceleration and acceleration curvature is instructive.
What we have called the Integrated Feedback model projected by the UKMO, fails to make the obviously necessary distinction between budget-emissions [the size and control of which we can choose to effect] and feedback-emissions [the rate and control of which can't].
In a misleadingly simplistic way, the UKMO's model falsely suggests that we can 'keep control' of rising concentrations, no matter what the overall shape weight rate and date of the contraction profile is.
The latter Segregated Feedback separates budget-emissions from potential feedback-emissions, shows the gradual acceleration of these and the resulting concentrations paths and suggests what is both obvious and crucial, namely that the more we delay sizing and controlling budget emissions, the more we are likely to experience and also lose control of rising concentrations as the planet warms and self-generating positive feedback effects come into play.
In addition to concentrations from 'Budget Emissions, these concentration pathways' from Segregated Feedback include the advent of non-human [non-budget] 'feedback-emissions'.
In other words, these concentration-pathways have momentum and once established, these will not just suddenly change direction or disappear. On the contrary, as the planet warms the acceleration will 'persist'.
So climate-policy based on the precautionary principle indicates we should avoid getting on a concentrations-pathway that is high enough to develop a life of its own, in other words where self-propagating positive-feedback effects take over and make human efforts at mitigation of merely human-budget-emissions futile.
CBAT user-choices of [a] budget, [b] slider-position, [c] feedback-type and [d] climate-sensitivity level [1-5] with all the resultant 'clock-values' on display, are presented to help connect users with the ranges of budget-choices and the increasingly possible and dangerous consequences of doing too-little too-late to define and control human-budget-emissions.