4.5.2 Cross-system interactions leading to cascades

The cross-system interactions within sociotechnical, socioecological and sociopolitical systems can lead to positive tipping cascades. Furthermore, the interactions across society, policy, technology and economy (Figure 4.5.1) can amplify these cascades. Historically, interacting political, technological and behavioural tipping elements such as the Montreal Protocol, development of non-Chlorofluorocarbon (CFCs) substitutes and public concerns over Ultra Violet (UV) radiation and skin cancer, led to a rapid phase-out of ozone-depleting chemicals (Stadelmann-Steffen et al., 2021).

In the near term, cascades across those systems can also lead to rapid decarbonisation. For instance, public procurement of sustainable food can accelerate norm and behaviour changes, enable the use of alternative agricultural practices, such as regenerative agriculture or green ammonia use, by reducing the land pressure, and (with the latter) can facilitate the decarbonisation of energy and transport systems by boosting the production of green hydrogen. Similarly, zero emission vehicle (ZEV) mandates are a strong leverage point due to cascading effects. As policies require manufacturers to ensure ZEVs account for rising proportion of their car sales, they overcome a constraint on supply in the transport sector, facilitate decarbonisation in the energy sector through innovation and raise the demand from the society. Versions of this policy have proved highly effective in California, China and the Canadian provinces of Quebec and British Columbia, combined with installation of charging stations.  

Not only public authorities and governments, but many different agents can play a role in triggering the cascades. For instance, thought leaders and media can be pivotal in enhancing the visibility of a population already engaged in climate action, which determines not only the demand for low-carbon goods and services, but also increases the momentum of climate policies and the perceived risk of fossil fuel assets. When such policies and financial developments reduce the fossil fuel supply, the resulting lower costs of low-carbon technologies lead to more people taking climate action by choosing low-carbon options, and creating a reinforcing feedback loop of cross-system cascades (Eker and Wilson, 2022).  

Below, we describe these interactions within and between the sociotechnical (energy, transport), socioecological (food and land use) and sociopolitical (society and policy, including finance) systems to highlight the role and ability of various agents in triggering cascades.