Is global warming leading to another glaciation? From science fiction to reality

Global warming is an irreversible consequence of the extensive and rapid emission and transfer of anthropogenic greenhouse gases, especially carbon dioxide from fossil fuel sources, into the Earth's atmosphere. For several decades, it has been recognized as the foremost environmental challenge confronting modern societies. The ongoing escalation in global temperatures is without precedent in the history of Earth's climate system.

At present, we are witnessing a discernible decline in the dynamics of the Atlantic Meridional Overturning Circulation (AMOC), a pivotal oceanic process governing the exchange of warm surface waters from north to south and back within the Atlantic Ocean over long cycles. AMOC serves as a vital conveyor belt, transporting heat and nutrients critical for sustaining marine ecosystems. The weakening of AMOC carries the potential to induce substantial seasonal temperature fluctuations—particularly colder winters—in the northern hemisphere. This phenomenon has been seized upon by proponents of climate change denial to question the urgency of addressing the issue through measures like reducing greenhouse gas (GHG) emissions.

In the science fiction film “The Day After Tomorrow,” the adverse effects of global warming and the repercussions of a diminished AMOC on the Earth's climate system are portrayed provocatively, replete with striking cinematographic effects that transcend the boundaries of human knowledge and imagination.

However, it's important to clarify that while a weakened AMOC may indeed lead to intermittent episodes of extreme cooling in the northern hemisphere, it will not precipitate a sudden onset of an ice age within a few weeks. The cyclical transition between glacial and interglacial periods is predominantly influenced by astronomical processes spanning tens of thousands of years. It is essential to mention that while a decelerating AMOC may contribute to mitigating global warming and climate change, this process alone cannot replace the necessity of attaining the current international emission reduction targets. This underscores the significance of worldwide cooperation in combating climate change.

The movie also touches upon two other themes that bear a striking resemblance to reality. Firstly, it touches on the issue of inaction stemming from the politicization and bureaucratic entanglement of the climate crisis, a predicament evident both in the film and in the real world. Secondly, it shows the geopolitical implications of global warming for modern society. Although regions in the Global South (Southern Hemisphere) are currently bearing the brunt of climate change vulnerabilities, they are paradoxically expected to experience lesser environmental impact, and will see massive migrations from the Global North as global warming continues. This highlights the need for sustainable climate-change policies and a major change in the global geopolitical agenda.

Additionally, these regions display special environmental, geological, ecological and socioeconomic features that differentiate them from the rest of the world and position them as global leaders in the sustainable implementation of both technological and nature-based climate solutions, playing a pivotal role in the emergence of carbon removal markets.