The Atlantic Ocean can handle more warming than expected — with one big catch
Scientists have found that the AMOC may be far more vulnerable to rapid warming than to temperature alone. When warming happens slowly, the ocean can adapt, but at faster rates similar to today’s, the massive Atlantic circulation could reach a tipping point at much lower temperatures.
New research from Utrecht University reveals that the speed of global warming plays a crucial role in the stability of the Atlantic Meridional Overturning Circulation (AMOC), a key ocean current system. The study challenges the long-held belief that a specific temperature threshold alone determines the fate of this circulation system. While temperature remains important, the researchers found that the rate of warming also significantly impacts the AMOC's stability.
The study, published in Nature Climate Change, reveals that two worlds with the same eventual temperature could experience vastly different outcomes for the AMOC, depending on the speed at which the warming occurs. Using climate models, the researchers simulated two scenarios: one with slow warming (0.5 ppm CO2 increase per year) and another with rapid warming (2.5 ppm CO2 increase per year).
The results showed that under slow warming, the AMOC remained stable even after crossing the previously estimated tipping point of +4°C. However, in the faster warming scenario, the AMOC collapsed at around +2°C.
Lead author René van Westen explains that this difference is due to the ocean's ability to adapt to changing conditions. With slower warming, the entire ocean—from surface layers to the deepest depths—has time to gradually reorganize and adapt. In contrast, rapid warming leaves the ocean unable to keep up, making it more vulnerable to instability.
Co-author Henk Dijkstra, a professor of Dynamical Oceanography, emphasizes that slow climate change allows the ocean to adjust throughout its full depth, while rapid warming leaves the circulation more vulnerable. The critical warming rate identified by the researchers is around 0.3°C per decade, which the world is currently approaching.
The research highlights the importance of not only limiting the eventual peak in global temperature but also slowing the rate of warming. The findings may have significant implications for climate policy, as they suggest that reducing the pace of warming could help mitigate the near-term risk of an AMOC collapse. This could be valuable for policymakers focused on reducing greenhouse gas emissions and mitigating climate change impacts.
Written by urgent.news from ScienceDaily's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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