Heinze, C., Blenckner, T., Martins, H., Rusiecka, D., Döscher, R., Gehlen, M., Gruber, N., Holland, E., Hov, Ø., Joos, F., Matthews, J. B. R., Rødven, R., & Wilson, S. (2021). The quiet crossing of ocean tipping points. Proceedings of the National Academy of Sciences, 118(9), https://doi.org/10.1073/pnas.2008478118
Summary:
Anthropogenic climate change profoundly alters the ocean’s environmental conditions, which, in turn, impact marine ecosystems. Some of these changes are happening fast and may be difficult to reverse. The identification and monitoring of such changes, which also includes tipping points, is an ongoing and emerging research effort. Prevention of negative impacts requires mitigation efforts based on feasible research-based pathways. Climate-induced tipping points are traditionally associated with singular catastrophic events (relative to natural variations) of dramatic negative impact. High-probability high-impact ocean tipping points due to warming, ocean acidification, and deoxygenation may be more fragmented both regionally and in time but add up to global dimensions. These tipping points in combination with gradual changes need to be addressed as seriously as singular catastrophic events in order to prevent the cumulative and often compounding negative societal and Earth system impacts. This study highlights four promising options in Earth system management and societal transformation for minimising the likelihood of encountering high-probability high-impact ocean tipping points.
1) GHG emission reductions need to be realized, 2) A sound global resource management needs to be implemented, 3) The implementation of mitigation measures needs to be enabled through adequate governance structures and seamless interagency action, 4) Transformations need to be carried out increasingly fast. The physical−chemical−biological ocean systems are at the verge of tipping into another state in many oceanic regions. Integrated over the world ocean, this adds up to a global issue of concern.
Policy relevant message:
The physical−chemical−biological ocean systems are at the verge of tipping into another state in many oceanic regions. Integrated over the world ocean, this adds up to a global issue of concern. The adverse impacts of human-induced climate change on the ocean can still be minimised. “Earth system targets,” like global warming or ocean acidification levels, and corresponding emission reduction targets need to be identified, agreed on, implemented, and verified. This study highlights four promising options in Earth system management and societal transformation for minimizing the likelihood of encountering high-probability high-impact ocean tipping points: 1) GHG emission reductions need to be realized, 2) A sound global resource management needs to be implemented, 3) The implementation of mitigation measures needs to be enabled through adequate governance structures and seamless interagency action, 4) Transformations need to be carried out increasingly fast.