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).
As in natural systems, tipping points in human systems are driven by self-reinforcing (mathematically ‘positive’) feedbacks: an increase in a variable leads to a closed loop of causal consequences that further increase the same variable. For example, one person or organisation’s decision to take the train rather than fly, or install solar panels, or pedestrianise a road, can increase the determination of others to do likewise. Such feedbacks are instrumental both in the enabling phase before a tipping point is reached and in the acceleration phase once a tipping point has passed (Figure 4.2.4). They can exist in any domain of human systems (social, economic, political and technological) and in their interactions with natural systems. For example, the self-reinforcing feedbacks of economies of scale and learning by doing have reduced the cost of solar PV and wind for energy generation to below that of coal power, with the result that most new power generation installed globally in 2022 was renewable (IEA, 2022).
Synergies between self-reinforcing feedbacks across multiple domains can help policymakers further enable the conditions for positive tipping (Fesenfeld et al., 2022, Pahle, 2018). Fesenfeld et al., (2022) highlight that synergies between policy-induced technological and behavioural changes can create self-reinforcing feedbacks and political conditions for positive tipping. For example, the German Renewable Energy Sources Act (EEG) triggered synergistic feedback effects in financial investment, technological innovation and cost reductions of renewable energy (Schmidt and Sewerin, 2018). Other self-reinforcing feedbacks associated with such policy interventions include shifts in public opinion, social norms and practices in favour of renewable energy, which in turn can reduce political opposition and create windows of opportunity for more stringent policy options, such as carbon taxation (Figure 4.2.4) (Fesenfeld et al., 2022; Lockwood, 2013; Schmid et al., 2019). Building on this logic in socio-technical transitions research, Geels and Ayoub (2023) distinguished seven feedback loops between behaviours of different social actors and technological changes in tipping dynamics.
Moreover, feedback and spillover effects between regions can play an important role in catalysing global change. For example, the German feed-in tariff created a first marketplace for solar PV panels that in turn has led to economies of scale in the production process of such panels in China. This has led to substantial cost reductions of solar panels so that PV became an attractive clean technology option at the global level. In turn, this has created a political momentum for change in other regions, such as China, the EU and US. In the transport sector, macro-economic modelling shows that mandates for switching to electric vehicles in major automobile markets such as China, the US or Europe can help to accelerate tipping points in other markets (Lam and Mercure, 2022).