The Southern Ocean has been absorbing carbon dioxide and heat from human activities for over a century, but this may lead to significant consequences when we cease fossil fuel emissions. A new study by German climate scientists predicts that when greenhouse gas emissions finally stop and the world begins to cool, the Southern Ocean will release a sudden surge of heat, warming the planet for at least another century.
Using a climate framework that integrates various models, the study simulates future climate scenarios. It suggests that while carbon emissions will peak within 70 years—potentially doubling atmospheric CO2—there will be a rapid reduction in emissions, leading to a gradual cooling over centuries.
The research indicates key factors behind ocean heat retention, including reduced natural heat loss due to climate change and the accumulation of warmth in deeper ocean layers. As surface temperatures take longer to cool, the ocean continues to absorb heat even after emissions decline. The melted sea ice also enhances the ocean’s heat absorption.
The findings suggest that once the Southern Ocean releases this stored heat, it will cause warming, particularly impacting countries in the Global South more severely. This challenges the belief that cumulative CO2 emissions and global warming are closely linked, raising concerns about the timeline for realizing the benefits of climate action, which may extend centuries beyond reaching net negative emissions.
The study emphasizes that the impact of climate action may not be felt immediately, as the world will remain warm long after fossil fuel use ends, and delaying action could intensify future warming. These insights were published in AGU Advances.
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