Ocean Circulation and Climate
By storing and transporting enormous quantities of heat and carbon and overturning on timescales from years to millennia, the ocean is the slow, powerful regulator at the heart of Earth's climate.
Definition
Ocean circulation and climate is the study of the large-scale movement of ocean water and its central role in regulating the climate system through the transport and storage of heat, freshwater, and carbon.
Scope
This area covers the global overturning (thermohaline) circulation and deep-water formation, the coupled interaction of ocean and atmosphere including phenomena such as El Nino, the ocean's uptake and storage of heat and carbon, and the consequences of a warming ocean including sea-level rise.
Sub-topics
Core questions
- How does the global overturning circulation move heat and carbon through the deep ocean?
- How do ocean and atmosphere interact to produce climate variability such as El Nino?
- How much of the planet's excess heat and carbon does the ocean absorb?
- How does ocean warming drive sea-level rise and other climate impacts?
Key theories
- Global overturning (conveyor) circulation
- Density-driven sinking of cold, salty water in polar regions and its slow return drives a global overturning that redistributes heat and carbon over centuries to millennia.
- Ocean-atmosphere coupling
- Two-way exchanges of heat, moisture, and momentum couple the ocean and atmosphere, giving rise to climate modes such as El Nino-Southern Oscillation that drive global variability.
Clinical relevance
The ocean's circulation and capacity to absorb heat and carbon determine the pace of global warming, drive seasonal-to-decadal climate prediction through phenomena like El Nino, and govern sea-level rise, making this area foundational to understanding and projecting climate change.
History
Recognition of the ocean's climatic role grew from early water-mass studies, Stommel's mid-century circulation theory, and Bjerknes's 1969 explanation of El Nino as ocean-atmosphere coupling. Broecker's conveyor-belt concept in the 1980s-1990s, combined with global observing systems and models, established the ocean as a central climate component.
Key figures
- Wallace Broecker
- Henry Stommel
- Carl Wunsch
- Jacob Bjerknes
Related topics
Seminal works
- talley2011
- broecker1991
Frequently asked questions
- Why is the ocean so important for climate?
- The ocean holds far more heat and carbon than the atmosphere and moves them around the globe, so it absorbs most of the excess heat from global warming and a large share of human carbon emissions, slowing but not stopping climate change.
- What is the ocean conveyor belt?
- It is a popular name for the global overturning circulation, in which dense water sinks in polar seas and flows through the deep ocean before slowly rising and returning, transporting heat and carbon worldwide.