Early warning signals in chemical reaction networks.

Complex systems such as ecosystems, the climate and stock markets produce emergent behaviour which is capable of undergoing dramatic change when pushed beyond a tipping point. Such complex systems display Early Warning Signals in their behaviour when they are close to a tipping point. Here we show that a complex chemical reaction network can also display early warning signals when it is in close proximity to the boundary between oscillatory and steady state concentration behaviours. We identify early warning signals using both an active sensing method, based on the recovery time of an oscillatory response after a perturbation in temperature, and a passive sensing method, based upon a change in the shape of the oscillations. The presence of the early warning signals indicates that complex, dissipative chemical networks can intrinsically sense their proximity to a boundary between behaviours.