A recent study published in Science by researchers from the University of California, Riverside raises a disruptive hypothesis: global warming could trigger a new ice age.
This possibility arises from incorporating an oceanic feedback mechanism that has been absent in traditional climate models.
The carbon cycle and rock erosion: the planet’s natural thermostat
Rain captures CO₂, transports it to the oceans, and fixes it in the seabed for millions of years.
According to geologist Andy Ridgwell, a co-author of the study, the Earth’s climate self-regulates through rock erosion. Rain dissolves minerals that reach the sea and transform into shells and reefs, sequestering carbon.
Higher temperatures lead to increased erosion, more CO₂ capture, and eventual cooling. However, this model does not explain the occurrence of extreme glaciations that happened before complex life.
The role of plankton and oceanic feedback
More phosphorus, more plankton, less oxygen: a cycle that buries carbon and cools the planet.
The study incorporates an additional process: the growth of oceanic plankton. The increase in CO₂ intensifies rainfall, carrying nutrients such as phosphorus to the sea.
This feeds the plankton, which absorbs CO₂ and buries it upon death. However, in warm waters with high biological activity, oxygen decreases, preventing phosphorus from being buried and causing its recycling, which feeds back into the cycle and buries even more carbon.
“The Earth’s thermostat isn’t broken, but it might not be in the same room as the air conditioner,” Ridgwell illustrated.
Implications of the model: “ice age,” but in the long term
Oceanic feedback could trigger a glaciation, but not in time to counteract current warming.
Although atmospheric oxygen currently moderates this mechanism, the model predicts that anthropogenic warming could be followed, in thousands of years, by an abrupt cooling. However, the authors warn that this should not be used as an excuse to not act today.
- Slow response time: cooling would take millennia
- Imminent current impact: extreme events, food crises, and displacements are already happening
- Human responsibility: limiting current warming remains urgent
A call to informed and responsible action
Science progresses, but climate urgency demands immediate decisions.
This study adds a new dimension to understanding the climate system, but also reinforces the need to act now. The complexity of the planet does not guarantee automatic solutions.
Human action remains the decisive factor in avoiding extreme scenarios.
