The concept of “planetary boundaries” is based on the fact that human actions are the main drivers of environmental changes, while the planet has a limited ability to adjust to these changes (Rockström et al. 2009; Rockström 2018a; Rockström 2018b). Nine planetary boundaries have been identified (Figure 1.2). It is estimated that humanity has already exceeded two of them: biosphere integrity and biochemical flows. Other boundaries are in danger of being exceeded. We lack adequate data about some of these boundaries, such as atmospheric aerosol loading. More information about planetary boundaries and tipping points is presented on the website of the Stockholm Resilience Centre, which includes several online videos (Stockholm Resilience Centre 2019; Lenton et al. 2019).
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Below boundary (safe)
In zone of uncertainty (increasing risk)
Figure 1.2 Planetary boundaries Source: Steffen et al. (2015).
