Britannica
Sources used in this answer
- global warming - Carbon cycle feedbacks
- Climate change - What are climate change and global warming?
- What’s the Difference Between Global Warming and Climate Change?
- global warming - The greenhouse effect
- seawater - Temperature distribution
- climate - Climate and the oceans
- global warming - Modern observations
Why can Earth continue warming even after greenhouse gas emissions are reduced?
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Global warming
A series of photographs of the Grinnell Glacier taken from the summit of Mount Gould in Glacier National Park, Montana, in (from left) 1938, 1981, 1998, and 2006. In 1938 the Grinnell Glacier filled the entire area at the bottom of the image. By 2006 it had largely disappeared from this view.
Earth can continue to warm even after greenhouse gas emissions are reduced due to several critical factors inherent in the climate system:
- Ocean Heat Storage: The oceans act as a massive reservoir for heat, possessing a much higher heat capacity than the atmosphere. Heat absorbed by the oceans can be buried beneath the surface or circulate in deep waters for years, meaning the climate system retains significant thermal energy that continues to influence surface temperatures long after emissions decline.12
- Feedback Mechanisms: Positive feedback loops can sustain warming even if the initial driver (greenhouse gas concentrations) is curtailed. For example, as temperatures rise, the capacity of the biosphere and oceans to sequester carbon may decrease, potentially turning these natural sinks into carbon sources. Additionally, the melting of Arctic permafrost can release trapped methane, a potent greenhouse gas, further driving warming.3
- System Equilibrium: The Earth's climate system requires time to reach thermodynamic equilibrium in response to changes in atmospheric composition. Because greenhouse gases continue to trap infrared radiation, the planet may continue to warm until the energy balance is restored.45