Despite more than two decades of diplomatic effort, concentrations of greenhouse gases continue to trend upwards, creating the risk that we may someday cross a threshold for ‘dangerous’ climate change1, 2, 3. Although climate thresholds are very uncertain, new research is trying to devise ‘early warning signals’ of an approaching tipping point4, 5, 6, 7, 8, 9, 10, 11. This research offers a tantalizing promise: whereas collective action fails when threshold uncertainty is large, reductions in this uncertainty may bring about the behavioural change needed to avert a climate ‘catastrophe’5. Here we present the results of an experiment, rooted in a game-theoretic model, showing that behaviour differs markedly either side of a dividing line for threshold uncertainty. On one side of the dividing line, where threshold uncertainty is relatively large, free riding proves irresistible and trust illusive, making it virtually inevitable that the tipping point will be crossed. On the other side, where threshold uncertainty is small, the incentive to coordinate is strong and trust more robust, often leading the players to avoid crossing the tipping point. Our results show that uncertainty must be reduced to this ‘good’ side of the dividing line to stimulate the behavioural shift needed to avoid ‘dangerous’ climate change.
At a glance
- Abrupt climate change. Science 299, 2005–2010 (2003). et al.
- Tipping elements in the earth’s climate system. Proc. Natl Acad. Sci. USA 105, 1786–1793 (2008). et al.
- Imprecise probability assessment of tipping points in the climate system. Proc. Natl Acad. Sci. USA 106, 5041–5046 (2009). , , , &
- Slowing down as an early warning signal for abrupt climate change. Proc. Natl Acad. Sci. USA 105, 14308–14312 (2008). et al.
- Turning back from the brink: Detecting an impending regime shift in time to avert it. Proc. Natl Acad. Sci. USA 106, 826–831 (2009). , &
- 2009). Critical Transitions in Nature and Society (Princeton Univ. Press,
- Early-warning signals for critical transitions. Nature 461, 53–59 (2009). et al.
- Tipping points: Early warning and wishful thinking. Geophys. Res. Lett. 37, L19703 (2010). &
- Early warning of climate tipping points. Nature Clim. Change 1, 201–209 (2011).
- Anticipating critical transitions. Science 338, 344–348 (2012). et al.
- Early warning of climate tipping points from critical slowing down: Comparing methods to improve robustness. Phil. Trans. R. Soc. A. 370, 1185–1204 (2012). , , , &
- Early warnings of regime shifts: A whole-ecosystem experiment. Science 332, 1079–1082 (2011). et al.
- Flickering gives early warning signals of a critical transition to a eutrophic lake state. Nature 492, 419–422 (2012). et al.
- Catastrophic shifts in ecosystems. Nature 413, 591–596 (2001). , , , &
- Generic indicators for loss of resilience before a tipping point leading to population collapse. Science 336, 1175–1177 (2012). , , &
- Complex systems: Ecology for bankers. Nature 451, 893–895 (2008). , &
- The urgency of the development of CO2 capture from ambient air. Proc. Natl Acad. Sci. USA 109, 13156–13162 (2012). et al.
- Warming caused by cumulative carbon emissions towards the trillionth tonne. Nature 458, 1163–1166 (2009). et al.
- Setting cumulative emissions targets to reduce the risk of dangerous climate change. Proc. Natl Acad. Sci. USA 106, 16129–16134 (2009). , , &
- Climate treaties and approaching catastrophes. J. Environ. Econ. Manage. 66, 235–250 (2013).
- Climate negotiations under scientific uncertainty. Proc. Natl Acad. Sci. USA 109, 17372–17376 (2012). &
- 111–194 (Princeton Univ. Press, 1995). in Handbook of Experimental Economics (eds Kagel, J. H. & Roth, A. E.)
- A safe operating safe for humanity. Nature 461, 472–475 (2009). et al.
- Integrating tipping points into climate impact assessments. Climatic Change 117, 585–597. &
- Multistability and critical thresholds of the Greenland ice sheet. Nature Clim. Change 2, 429–432 (2012). , &
- Bistability of the Atlantic overturning circulation in a global climate model and links to ocean freshwater transport. Geophys. Res. Lett. 38, L10605 (2011). et al.
- The stability of the MOC as diagnosed from model projections for pre-industrial, present and future climates. Clim. Dynam. 37, 1575–1586 (2010). , &
- Regime shifts in ecological systems can occur with no warning. Ecol. Lett. 13, 464–472 (2010). &
- 1990). Governing the Commons: The Evolution of Institutions for Collective Action (Cambridge Univ. Press,
- 2003). Environment and Statecraft: The Strategy of Environmental Treaty-Making (Oxford Univ. Press,