Harmful tipping points in the natural world pose some of the gravest threats faced by humanity. Their triggering will severely damage our planet’s life-support systems and threaten the stability of our societies.
In the Summary Report:
• Narrative summary
• Global tipping points infographic
• Key messages
• Key Recommendations
Executive summary
• Section 1
• Section 2
• Section 3
• Section 4
This report is for all those concerned with tackling escalating Earth system change and mobilising transformative social change to alter that trajectory, achieve sustainability and promote social justice.
In this section:
• Foreword
• Introduction
• Key Concepts
• Approach
• References
Considers Earth system tipping points. These are reviewed and assessed across the three major domains of the cryosphere, biosphere and circulation of the oceans and atmosphere. We then consider the interactions and potential cascades of Earth system tipping points, followed by an assessment of early warning signals for Earth system tipping points.
Considers tipping point impacts. First we look at the human impacts of Earth system tipping points, then the potential couplings to negative tipping points in human systems. Next we assess the potential for cascading and compounding systemic risk, before considering the potential for early warning of impact tipping points.
Considers how to govern Earth system tipping points and their associated risks. We look at governance of mitigation, prevention and stabilisation then we focus on governance of impacts, including adaptation, vulnerability and loss and damage. Finally, we assess the need for knowledge generation at the science-policy interface.
Focuses on positive tipping points in technology, the economy and society. It provides a framework for understanding and acting on positive tipping points. We highlight illustrative case studies across energy, food and transport and mobility systems, with a focus on demand-side solutions (which have previously received limited attention).
The majority of studies on early warnings of Earth system tipping points are based on searching for evidence of CSD. Essentially, if a system is forced towards a tipping point, the state it currently occupies starts to lose its stability as the restoring feedbacks that ‘pull’ the system back to that state after it is perturbed start to weaken. If the system is forced sufficiently slowly that it can remain close to steady state, this causes the system to respond more sluggishly to short-term perturbations, and thus ‘slow down’ (Wissel, 1984).
Figure 1.6.1 shows this concept visually using the ‘ball in potential well’ analogy. When the system is more stable (represented by the well with steeper sides) recovery from any given perturbation is faster (the ball returns faster). A system closer to tipping (represented by a shallower well) has a slower recovery from the same perturbation (the ball takes longer to return). Eventually, the restoring feedbacks of the system become so weak at a tipping point that the stability of the initial state is lost, and the system moves to a new stable state. Before that point a random disturbance may cause the system to exit its initial state early.
The occurrence of CSD prior to a critical transition has been identified across numerous domains (Kubo, 1966; Kawasaki, 1966; Ferrell, 1970; Wissel, 1984; Dakos et al., 2023). In most cases, it mathematically involves the leading ‘eigenvalue’ of the system (which describes the strength of damping negative feedback) approaching 0 from below. However, in reality we typically do not have the equations that govern the system’s dynamics, and as such have to estimate the occurrence of CSD with methods detailed in this chapter.