The quiet crossing of ocean tipping points

Abstract

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.

Tipping point realized in cod fishery

“…The potential existence of tipping points in dynamic systems is an active field of research because they imply unexpected and sudden changes that are difficult or even impossible to reverse 1 , 2 . Understanding processes leading to tipping points is also of crucial importance for fisheries management since ignoring such non-linear and discontinuous dynamics can cause unexpected collapses of ecologically, culturally and economically important resources 3 , and may render subsequent recovery efforts unsuccessful 4 .…”

A global map of human pressures on tropical coral reefs

“…With the planet's oceans facing committed warming for decades and predicted to cross a series of climate tipping points (Heinze et al, 2021), ensuring human impacts are effectively managed is urgently required to meet climate adaptation targets of the United Nations Framework Convention on Climate Change and are a key vision of the Post-2020 Biodiversity Framework of the Convention on Biological Diversity. With local pressures expected to expand and intensify over time, particularly with increasing climate change (O'Hara, Frazier, & Halpern 2021), tracking and mitigating these impacts of local pressures also requires access to global data layers (e.g., Halpern 2020).…”

Ten new insights in climate science 2021: a horizon scan

“…Yet, marine ecosystems are exposed to manifold impacts of climate change and other anthropogenic pressures that are accelerating in magnitude and extent (Jouffray et al, 2020). This includes ocean warming, acidification, deoxygenation and extreme events, as well as exploitation, mining, pollution (nutrients eutrophication, toxins, organic waste, plastics, litter), habitat destruction, unsustainable fishing and aquaculture, invasive species and shipping (Bates & Johnson, 2020;Boyce et al, 2020;Glibert, 2020;Heinze et al, 2021). Today, more than 1,300 marine species are threatened with extinction (Figure 5a), 34.2% of fish stocks are overexploited, most ocean areas experience the mentioned anthropogenic impacts cumulatively, and 33%-50% of vulnerable habitats have been lost (Duarte et al, 2020).…”