Oceans and climate

European Space Agency, ESA

26 May 202203:33

Summary

TLDRThe script highlights the critical role of oceans as vast heat reservoirs, absorbing 93% of excess heat from human activities over 70 years. Ocean currents, driven by winds and water density differences, redistribute heat globally, influencing weather and climate. Europe's mild climate is attributed to the Gulf Stream. Ocean heat waves can cause coral bleaching and habitat loss. Oceans also absorb CO2, leading to acidification and threatening marine life. Satellites monitor various ocean variables, including sea level, salinity, and ice cover, which are crucial for understanding climate regulation and the impacts of climate change on our oceans.

Takeaways

🌊 Oceans act as vast heat reservoirs, absorbing 93% of the excess heat from human activity over the past 70 years.
🔄 Ocean currents play a vital role in redistributing heat globally, with surface currents driven by winds and deep currents by water density differences due to temperature and salinity.
🌡️ The distribution of ocean heat influences weather patterns and regional climates, exemplified by Europe's mild climate due to the warm Gulf Stream and North Atlantic Current.
🌡️ Ocean heat waves can have detrimental effects, such as coral bleaching, habitat loss, and the absorption of heat by oceans.
🌿 Oceans also serve as a natural carbon sink, absorbing about a quarter of carbon dioxide emissions from human activity, leading to ocean acidification and threats to marine life.
🔬 The amount of heat and carbon dioxide absorbed by oceans depends on various factors including phytoplankton, temperature, waves, salinity, and ice cover, all of which can be monitored from space.
🛰️ Satellites are capable of measuring sea level and slope, allowing for the derivation of surface currents.
🌧️ Ocean salinity maps reveal regions of evaporation, precipitation, and river inflow, with high salinity in enclosed basins like the Mediterranean Sea due to high evaporation.
❄️ Ocean salinity increases in areas where sea ice forms, as salt is left behind when water freezes, contributing to the thermo-haline circulation.
🌀 The thermo-haline circulation is essential for global climate regulation and drives surface currents like the Gulf Stream.
☁️ There are signs that the thermo-haline overturning in the North Atlantic is weakening, which could lead to cooler air over Europe and more winter storms, as well as higher sea levels and more powerful hurricanes along the Atlantic coast of North America.
🌍 East's climate change initiative is generating long-term datasets to understand the influence of oceans on climate and the impact of climate change on our oceans.

Q & A

What role do oceans play in storing heat from human activity?
-Oceans act as massive heat stores, having absorbed 93% of the excess heat from human activity over the past 70 years.
How do ocean currents redistribute heat around the planet?
-Ocean currents redistribute heat from the equator to the poles, with surface currents primarily driven by winds and deep currents caused by differences in water density due to temperature and salinity.
Why is Europe's climate mild?
-Europe's mild climate is attributed to the warm Gulf Stream and North Atlantic Current, which transport warm water from the equator to higher latitudes.
What are the consequences of ocean heat waves on marine life?
-Ocean heat waves can lead to coral bleaching, habitat loss, and other detrimental effects on marine ecosystems.
How do oceans act as a carbon sink and what is the impact of this on ocean water?
-Oceans absorb about a quarter of carbon dioxide emissions from human activity, which has led to the acidification of ocean water, threatening marine life.
What factors determine the amount of heat and carbon dioxide absorbed by oceans?
-The amount of heat and carbon dioxide absorbed by oceans depends on variables such as phytoplankton, temperature, waves, salinity, and ice cover.
How can satellites measure and monitor ocean conditions from space?
-Satellites can measure sea level, slope, and salinity, from which surface currents and regions of evaporation, precipitation, and river inflow can be derived.
Why does the Mediterranean Sea have high salinity?
-The Mediterranean Sea has high salinity due to high evaporation rates in its enclosed basin, leaving behind salt as water evaporates.
What is the thermo-haline circulation and why is it important for global climate regulation?
-The thermo-haline circulation is a centuries-long journey of cold, salty, dense water sinking into the ocean's depths, which is crucial for regulating global climate and driving surface currents like the Gulf Stream.
What signs indicate that the overturning in the North Atlantic is weakening, and what could be the consequences?
-There are signs that the North Atlantic's overturning is weakening, which could lead to cooler air over Europe, more winter storms, and potentially higher sea levels, warmer waters, and more powerful hurricanes along the Atlantic coast of North America.
How is East's climate change initiative contributing to our understanding of oceans and climate?
-East's climate change initiative is producing long-term data sets that help us understand how oceans influence climate and how the changing climate is affecting our oceans.

Outlines

00:00

🌊 Oceans as Global Heat Regulators

The script discusses the critical role oceans play in regulating Earth's climate by storing heat and redistributing it through ocean currents. It explains how these currents are influenced by winds at the surface and by differences in water density due to temperature and salinity at depth. The Gulf Stream and North Atlantic Current are highlighted as examples of how ocean currents contribute to Europe's mild climate. The script also touches on the negative impacts of ocean heat waves, such as coral bleaching and habitat loss, and the ocean's role as a carbon sink, which has led to the acidification of ocean water and threats to marine life.

🌡️ Measuring Ocean Variables from Space

This section of the script focuses on the technological capabilities that allow us to monitor and measure various ocean variables from space. Satellites are used to measure sea level and slope, which helps in deriving surface currents. Additionally, ocean salinity maps are created to show regions of evaporation, precipitation, and river inflow. The script explains how high salinity in the Mediterranean Sea is due to high evaporation rates, while other areas experience lowered salinity due to rainfall and upwelling. The importance of salinity in the thermo-haline circulation, which is a centuries-long journey of cold, salty, dense water sinking into the ocean's depths, is also emphasized. This vertical overturning is crucial for global climate regulation and drives surface currents like the Gulf Stream.

🌪️ Climate Change and Ocean Currents

The script addresses the potential consequences of climate change on ocean currents and global weather patterns. It mentions signs of weakening overturning in the North Atlantic, which could lead to cooler air temperatures over Europe and an increase in winter storms. The Atlantic coast of North America may face higher sea levels, warmer waters, and more powerful hurricanes due to these changes. The script concludes by highlighting the importance of climate change initiatives that produce long-term data sets, aiding in the understanding of how oceans influence climate and how the changing climate affects our oceans.

Mindmap

Keywords

💡Ocean Heat Stores

Ocean heat stores refer to the oceans' capacity to absorb and retain heat from various sources, including human activities. In the video's context, it is mentioned that oceans have absorbed 93% of the excess heat from human activity over the past 70 years. This plays a significant role in the global climate system by redistributing heat and influencing weather patterns.

💡Ocean Currents

Ocean currents are the continuous movement of ocean water in a specific direction, driven by various forces such as wind, temperature, and salinity differences. The video explains that these currents redistribute heat from the equator to the poles, affecting regional climates and weather patterns, with the Gulf Stream being a key example.

💡Thermohaline Circulation

Thermohaline circulation, also known as the ocean conveyor belt, is the process by which ocean water moves in a loop due to differences in temperature and salinity. The video script mentions that this vertical overturning is crucial for regulating the global climate and drives surface currents like the Gulf Stream.

💡Coral Bleaching

Coral bleaching is a phenomenon where corals lose their color and become white due to stress, often caused by increased water temperatures. The script highlights that ocean heat waves can lead to coral bleaching, which is a significant environmental concern as it results in habitat loss for marine life.

💡Carbon Sink

A carbon sink is a natural or artificial reservoir that absorbs more carbon dioxide (CO2) than it releases. The video explains that oceans are a natural carbon sink, absorbing about a quarter of the CO2 emissions from human activities, which has implications for the acidification of ocean water.

💡Ocean Acidification

Ocean acidification is the decrease in the pH of ocean waters caused by the uptake of CO2 from the atmosphere. The video mentions that the absorption of CO2 by oceans has led to acidification, which threatens marine life by altering the chemistry of seawater.

💡Salinity

Salinity refers to the saltiness of a body of water, typically measured in parts per thousand (ppt). The video script discusses how ocean salinity can be mapped and is influenced by factors such as evaporation, precipitation, and river inflow, which in turn affects ocean currents and climate regulation.

💡Sea Level

Sea level is the height of the ocean's surface in relation to a fixed reference point. The video mentions that satellites can measure sea level, which is important for understanding surface currents and the impacts of climate change on coastal areas.

💡Climate Change Initiative

A climate change initiative is a program or project aimed at understanding, mitigating, or adapting to climate change. The video script refers to East's climate change initiative, which is producing long-term datasets to help understand the influence of oceans on climate and the effects of climate change on oceans.

💡Gulf Stream

The Gulf Stream is a powerful and warm Atlantic Ocean current that originates in the Gulf of Mexico and flows towards Europe. The video script explains that Europe's mild climate is due to the warm Gulf Stream, illustrating the impact of ocean currents on regional climates.

💡Overturning

In the context of the video, overturning refers to the process where cold, dense water sinks in the ocean, while warm water rises to the surface. The script mentions signs that the overturning in the North Atlantic is weakening, which could lead to climate changes such as cooler air over Europe and more winter storms.

Highlights

Earth's oceans have absorbed 93% of excess heat from human activity over the past 70 years.

Ocean currents redistribute heat around the planet from the equator to the poles.

Surface ocean currents are driven mainly by winds, while deep currents are influenced by water density differences due to temperature and salinity.

The distribution of ocean heat influences weather patterns and regional climate.

Europe's mild climate is largely due to the warm Gulf Stream and North Atlantic Current.

Ocean heat waves can lead to coral bleaching and habitat loss.

Oceans act as natural carbon sinks, absorbing about a quarter of human-generated carbon dioxide emissions.

The absorption of carbon dioxide by oceans has led to ocean acidification, threatening marine life.

The amount of heat and carbon dioxide absorbed by oceans depends on variables like phytoplankton, temperature, waves, salinity, and ice cover.

Satellites can measure sea level, slope, and surface currents to provide data on ocean conditions.

Maps of ocean salinity reveal regions of evaporation, precipitation, and river inflow.

High evaporation in the Mediterranean Sea increases its salinity.

Ocean salinity rises in areas where sea ice forms, as salt is left behind when water freezes.

The thermo-haline circulation, a centuries-long vertical overturning of the ocean, is crucial for regulating global climate.

There are signs that the overturning in the North Atlantic is weakening, potentially leading to cooler air over Europe and more winter storms.