In the debate on climate change, it is argued that due to anthropogenic activities, the Earth is gradually reaching a tipping point (a phenomenon in which changes such as greenhouse gases gradually accumulate, resulting in dramatic changes after a certain point) with large-scale changes that are irreversible. The tipping point is believed to have been reached. There is concern that reaching the tipping point could lead to a Planetary Emergency, in which unforeseen events could fall like dominoes and become uncontrollable.

Tipping elements in the Earth system that are likely to exceed the tipping point include the melting of the Greenland ice sheet, permafrost melting, melting of the Antarctic ice sheet, and deforestation of the Amazon. In a recent article, we introduced research showing the ongoing melting of ice sheets and glaciers in various regions of the world. Although these events may seem disjointed at first glance, teleconnection occurs in the Earth system, and a critical situation in one subsystem spills over to other subsystems, causing a domino effect and an unexpected impact on the climate system.This could have unforeseen effects on the climate system. However, there is still much that is unknown about about the mechanism by which critical conditions in one system can affect other areas.

A paper recently published in Nature Climate Change pointed out that when one of the tipping elements, the Amazon Rainforest Area, reaches a tipping point, it can spill over to the seemingly distant Tibetan Plateau and have a significant impact (tipping cascade). According to the paper's model, there is a strong correlation between the Amazon Rainforest Area and various extreme weather events on the Tibetan Plateau under climate change. The paper also showed that snow cover on the Tibetan Plateau has been decreasing since 2008.　

Recent discussions suggest that the tipping point could occur with a 1-2°C temperature rise. Hence, the Paris Agreement calls for limiting warming to below 2°C and, whenever possible, below 1.5°C. The fact that the tipping element is remotely correlated means that there are no national borders in the fight against climate change, and countries are required to cooperate and take ambitious actions toward the international goal.

Reference
Liu, T., Chen, D., Yang, L. et al. Teleconnections among tipping elements in the Earth system. Nat. Clim. Chang. 13, 67-74 (2023). https://doi.org/10.1038/s41558-022-01558-4

Contributor: IIYAMA Miyuki (Information Program)