Imagine we detect a large asteroid heading straight for Earth. We are able to intervene and prevent disaster, but instead we cut the funding needed to track it. A few million dollars, it was argued, was too expensive to have a chance to save society.

While this scenario isn’t real, the metaphor is alarmingly accurate. In Europe, we spend €1bn to monitor space for asteroids, even if the actual risk of a civilisation-ending asteroid strike is close to zero.

But governments don’t commit to spend a fraction of that amount to adequately monitor a threat that is more imminent, more likely, and located here on Earth: a major change in the Atlantic Meridional Overturning Circulation (Amoc).

The Amoc is a vast system of ocean current that moves heat from the south to north in the Atlantic Ocean, thereby playing a crucial role in regulating global climate upon which modern civilisation is built – from agriculture, through infrastructure to health, prosperity and culture. Changes in Amoc can impact food security, coastal flooding, storms, energy demand, migration, infrastructure planning, etc.

Under current climate change, the Amoc is projected to weaken enough to radically change the weather and cause sea level rise in Europe. However, there is little consensus on when and how fast this will occur. Projections of the future Amoc vary between climate models, and while scientists continue to improve the ability of models to represent the real ocean, progress is hampered by insufficient understanding of the physics of the Amoc.

Consequently, this complicates matters for policymakers to implement........

© The Guardian