Is Climate Change Slowing Down the Ocean? | Susan Lozier | TED

Summary

The video script discusses the importance of understanding and monitoring the 'ocean overturning circulation,' a vital process that redistributes heat on our planet and plays a significant role in our climate. It explains how the process works, starting from the sinking of cold, dense waters at high latitudes to their eventual upwelling and warming, completing the cycle. The script highlights concerns over the potential slowing or collapse of this circulation due to climate change, which could lead to severe disruptions in climate and weather patterns. It emphasizes the need for global measurements and collective action to reduce carbon dioxide emissions to mitigate these risks. The speaker also underscores the urgency of addressing climate change within the next nine years, calling for a unified effort to protect our oceans and planet.

Takeaways

• 📚 Adelard of Bath, a 12th-century philosopher, listed 76 unanswered questions about nature, including those relevant to oceanographers.
• 🌊 Oceanographers today are concerned with how climate change impacts navigation, marine ecosystems, and the potential collapse of ocean overturning circulation.
• 🔄 The ocean overturning circulation is a large-scale current system that redistributes heat on Earth, maintaining a 30-degree-Celsius difference between the equator and the poles.
• ❄️ In winter, cold winds convert warm surface waters to cold, dense waters that sink and spread across the globe, eventually upwelling and warming again.
• 🌡️ The overturning circulation also affects climate by carrying carbon dioxide absorbed from the atmosphere, which has increased ocean acidity and impacted marine life.
• 📈 The ocean has absorbed 30% of CO2 released by humans since the Industrial Revolution, but this carbon uptake is causing ocean acidification.
• 🌞 As the ocean warms and ice melts, surface waters may become less dense, potentially slowing the overturning circulation and leading to climate disruptions.
• ⏳ Oceanographers once believed overturning changed slowly, but evidence suggests it could change rapidly, within decades or even years.
• 📉 Climate models project a decline in overturning circulation by between 11% and 34% this century, which could cause significant climate disruptions.
• 🌍 Observations are crucial for improving predictions; the longer we measure, the better our understanding of the overturning circulation and its impacts.
• 🔬 International efforts like OSNAP are essential for global ocean measurements, providing data to understand and mitigate the effects of climate change.
• ⛵️ Advances in technology, such as autonomous gliders, enable more efficient data collection and monitoring of ocean conditions, even for those prone to seasickness.

Q & A

What was Adelard of Bath known for in the 12th century?

Adelard of Bath was a natural philosopher known for compiling a list of unanswered questions about the natural world, including phenomena related to the ocean.

Why are the waters of the sea salty, according to the script?

The script does not directly answer why the sea is salty, as this was one of the questions listed by Adelard of Bath that remained unanswered in his time.

What is the significance of the ocean overturning circulation in climate regulation?

The ocean overturning circulation is crucial for redistributing heat across the planet. It works in tandem with atmospheric circulation to maintain a significant temperature difference between the equator and the poles, which would otherwise be much more extreme.

How does the ocean overturning circulation affect carbon dioxide levels?

The ocean overturning circulation helps sequester carbon dioxide by carrying surface waters, which have absorbed atmospheric CO2, to deeper parts of the ocean. This process is essential for controlling atmospheric CO2 levels and mitigating global warming.

What are the potential impacts of a slowdown in the ocean overturning circulation?

A slowdown in the ocean overturning circulation could lead to reduced carbon uptake by the ocean, more extreme weather patterns, stronger hurricanes, and more intense precipitation.

Why might the ocean overturning circulation slow down?

The script suggests that as global warming continues and polar ice melts, the surface waters may become less dense and not sink during winter as they currently do, potentially causing a slowdown in the overturning circulation.

What role does the OSNAP monitoring system play in oceanographic research?

The OSNAP (Overturning in the Subpolar North Atlantic Program) system plays a crucial role by providing data on ocean currents, temperature, and salinity across the North Atlantic, helping scientists monitor and understand changes in the ocean overturning circulation.

How does modern technology enhance oceanographic studies?

Modern technology, like autonomous gliders and satellite communication, allows for more efficient and extensive data collection from remote parts of the ocean, aiding in real-time monitoring and research without the need for constant human presence.

What is the urgency of addressing oceanic and atmospheric changes mentioned in the script?

The script emphasizes the urgency of acting within the next nine years to mitigate adverse changes in the ocean and atmosphere, highlighting the critical time window to avert severe climate and ecological disruptions.

What is the main solution proposed to reduce the risk of an overturning circulation slowdown or shutdown?

The primary solution proposed in the script is a global effort to reduce atmospheric carbon dioxide levels, which involves collective action to address the root cause of climate change and its impacts on oceanic systems.