Our planet’s vital oceanic circulation systems are undergoing dramatic and unprecedented transformations, signalling a potential shift towards a new, more dangerous climate state. Recent satellite observations have revealed a surprising shift in the Southern Ocean's surface trends since 2015, with waters becoming significantly saltier and experiencing a rapid decline in sea ice. This abrupt change is allowing deep ocean heat to surge upwards and melt sea ice from below, creating a potentially dangerous feedback loop.
These developments near Antarctica raise urgent questions about the stability of another critical global circulation system: the Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream. The AMOC, a planetary ‘conveyor belt’ crucial for regulating global heat distribution and regional climates, especially in Europe and North America, is already at its lowest strength in over 1,000 years. Scientists are increasingly concerned that the Southern Ocean shift could not only escalate, but foreshadow or even contribute to an eventual collapse of the North Atlantic circulation.
What do these latest developments really mean? Why are different models saying different things? And how can we prepare?
Given the uncertainties around what is now playing out in the Southern Ocean, this week we pivoted to conduct an exclusive Age of Transformation Strategic Risk Assessment to explore these interconnected ocean changes, their potential to trigger cascading climate tipping points, and the profound implications for global climate stability and human civilization, particularly within the crucial horizon of mid-century. We are releasing this analysis free in the public interest.
The assessment highlights the risk of a “phase shift” in the earth system to a new, hotter, and less stable ‘Hothouse Earth’ state. It analyzes the severe consequences, including paradoxical cooling in Europe, widespread disruption of tropical rain belts, global food insecurity, regional sea-level rise, ecosystem collapse, and heightened societal instability, with many of these risks projected to become critical by mid-century (around 2050) under current high emissions scenarios.
The methodology employed in this risk assessment involves synthesizing insights from recent satellite observations, in-situ oceanographic data, peer-reviewed scientific studies, and climate model projections. By drawing upon these diverse sources, the report provides a comprehensive, urgent evaluation of these interconnected climate threats and their potential for abrupt, non-linear shifts in the Earth system.
