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).
For socio-behavioural change, policymakers are also important, as policies can have a great impact on shifting norms, behaviours and practices. For instance, the law banning smoking in closed public spaces has shifted society from a state where most smokers were inconsiderate to non-smokers, to a new equilibrium in which a large share of smokers are considerate, even in unregulated spaces (Nyborg and Rege., 2003). Policymakers can support the propagation of anti-fossil fuel norms by making political decisions that explicitly signal the end of the fossil fuel era, for instance by withdrawing from all oil extraction activities, as Denmark did in 2020, or mandating a ban on petrol/diesel car sales, as the UK did from 2030 (now put back to 2035). Additionally, governance interventions increase the visibility of certain behaviours and can help to establish emerging norms and the behaviours they prescribe.
Behaviours that are easily observable (e.g. smoking, mask wearing) may be more likely to show tipping dynamics due to the more prominent role of social norms and sanctioning in guiding those behaviours (Nyborg et al., 2016). Policies can explicitly increase visibility of desired behaviours. A study showed that making a behaviour observable tripled compliance, outperforming even cash incentives (Yoeli et al., 2013; Shrum 2021). Moreover, as far as targeting companies is concerned, regulatory climate shaming (e.g. through rankings, ratings, labelling, company reporting, lists or online databases based on corporate climate performance) can be quite effective. (Yadin, 2023).
Many climate-relevant behaviours are perfectly visible though, such as driving a petrol-fuelled car versus cycling or walking. In such cases, governance interventions must look for ways to break self-fulfilling expectations (Nyborg et al., 2016) – i.e. people need to believe that others will take up cycling or walking and policies can provide reasons for people to change their expectations. Costly public investments, like bicycle lanes, can change expectations about which behaviours are likely to prevail as they signal that incentives (and potentially social norms) have changed for everyone (Nyborg et al., 2016, see Chapter 4.3.2). Usually, several social, economic and other feedbacks are present and can dominate to various degrees.
Transitioning to new behaviours is often costly, particularly in terms of upfront costs. Behaviour and lifestyle changes are influenced by norms, but also by perceived and actual action control – i.e. people can only adopt behaviours that are possible and salient (Ajzen and Fishbein, 2005; Fritsche et al., 2018). Hence, if reinforcing social feedbacks (e.g. anti-fossil fuel norms) are present or emerging but dominated by disincentives (e.g. costs), policy can modify the latter through taxes, carbon fees with dividends, subsidies, or infrastructure investments (Nyborg et al., 2016; Stiglitz et al., 2017).