There is a diverging perception of climate tipping points, abrupt changes and surprises in the scientific community and the public. While such dynamics have been observed in the past, e.g., frequent reductions of the Atlantic meridional overturning circulation during the last ice age, or ice sheet collapses, tipping points might also be a possibility in an anthropogenically perturbed climate. In this context, high impact—low likelihood events, both in the physical realm as well as in ecosystems, will be potentially dangerous. Here we argue that a formalized assessment of the state of science is needed in order to establish a consensus on this issue and to reconcile diverging views. This has been the approach taken by the Intergovernmental Panel on Climate Change (IPCC). Since 1990, the IPCC has consistently generated robust consensus on several complex issues, ranging from the detection and attribution of climate change, the global carbon budget and climate sensitivity, to the projection of extreme events and their impact. Here, we suggest that a scientific assessment on tipping points, conducted collaboratively by the IPCC and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, would represent an ambitious yet necessary goal to be accomplished within the next decade.

科学界和公众对气候临界点、突变和意外存在不同的看法。虽然过去已经观察到这种动态，例如上一个冰河时期大西洋经向翻转环流的频繁减少或冰盖崩塌，但在人为扰动的气候中也可能出现临界点。在这种情况下，无论是在物理领域还是在生态系统中，高影响低可能性的事件都将具有潜在的危险。在这里，我们认为需要对科学状况进行正式评估，以便就这个问题达成共识并调和不同观点。这是政府间气候变化专门委员会（IPCC）采取的方法。自 1990 年以来，IPCC 一直在多个复杂问题上达成强有力的共识，从气候变化的发现和归因、全球碳预算和气候敏感性，到极端事件及其影响的预测。在此，我们建议，由政府间气候变化专门委员会和生物多样性和生态系统服务政府间科学政策平台合作进行的临界点科学评估，将是未来十年内要实现的雄心勃勃但必要的目标。