The Earth System

Summary

This video script delves into Earth's interconnected system components, illustrating the flow of matter, particularly carbon, between the atmosphere, hydrosphere, geosphere, and biosphere. It highlights the impact of human activities on carbon flux, especially the increase in atmospheric CO2 due to fossil fuel use and land changes. The script underscores the need to balance carbon emissions and absorption to mitigate climate change, offering insights into the Earth's complex, interdependent system.

Takeaways

• 🌏 The Earth's system is composed of interconnected components or 'spheres': the atmosphere, hydrosphere, geosphere, and biosphere.
• 🔄 Matter cycles between these components, with scientists considering the movement as the rate of flow or flux of materials between reservoirs.
• 🌊 Oceans serve as a simplified example of a reservoir, where water enters from rainfall and rivers and exits through evaporation to the atmosphere.
• 🧊 During the last ice age, sea levels dropped significantly due to trapped precipitation in ice sheets, preventing it from returning to the ocean.
• 🏔️ Recent glacier melting has increased the flow into the Earth's system, leading to a larger reservoir and a rise in global sea levels.
• 🌱 The carbon cycle is a key element in the Earth's system, with carbon moving among the components in various forms.
• 🌿 Plants in the biosphere take in carbon dioxide through photosynthesis, converting it into carbohydrates for growth.
• 💨 The concentration of atmospheric carbon dioxide has increased due to the use of fossil fuels, contributing to Earth's climate change.
• 🌊 Oceans play a crucial role in the carbon cycle by absorbing carbon dioxide from the atmosphere and forming calcite through marine organisms.
• 🗻 The geosphere, including fossil fuel reserves, is Earth's largest carbon reservoir, storing more carbon than the entire biosphere.
• 🔍 Human activities, particularly since the Industrial Revolution, have significantly perturbed the carbon cycle, leading to increased carbon release and atmospheric levels.
• 🌱 To mitigate the increase of carbon in the atmosphere, we need to either reduce carbon production or enhance carbon uptake by other Earth system components.

Q & A

What are the four main spheres of the Earth's system mentioned in the script?

The four main spheres of the Earth's system are the atmosphere, hydrosphere, geosphere, and biosphere.

How is matter exchanged between the Earth's system components?

Matter is exchanged between the Earth's system components through the flow or flux of materials moving into and out of a series of reservoirs.

What is a simplified example of a reservoir in the Earth's system?

A simplified example of a reservoir in the Earth's system is the oceans, where water circulates in from various sources like rainfall and rivers and flows out by evaporation to the atmosphere.

What happened to sea levels during the last ice age?

During the last ice age, frozen precipitation that fell on the continents was trapped in ice sheets and didn't return to the ocean, causing sea levels to drop significantly by more than a hundred meters.

How has the rate of melting of glaciers on the continents affected global sea levels in recent years?

In recent years, the rate of melting of glaciers on the continents has intensified, increasing the flow into the system, producing a larger reservoir and a rise in global sea levels.

What is the Keeling Curve and what does it represent?

The Keeling Curve is a plot that records the study increase of carbon dioxide in the atmosphere, showing the natural flow of carbon dioxide as well as the increase due to the greater use of carbon-rich fossil fuels.

How does carbon move from the atmosphere to the ocean?

Carbon dioxide and other gases are exchanged between the atmosphere and the ocean, where the carbon becomes part of a carbonate ion that combines with calcium to form the mineral calcite.

What is the role of the biosphere in the Earth's carbon cycle?

The biosphere, composed of all living organisms, plays a role in the carbon cycle by taking in carbon dioxide from the atmosphere through photosynthesis and combining it with other elements to form carbohydrates for growth.

How does carbon move from the biosphere to the geosphere?

Carbon moves from the biosphere to the geosphere when organisms that have incorporated carbon die, are buried, and compacted into layers of rock, such as limestone, on the seafloor.

What is the largest carbon reservoir in the Earth's system?

The geosphere, which includes the continents and ocean floors and the rocks and minerals in Earth's crust, mantle, and core, is the largest carbon reservoir in the Earth's system.

How has human activity affected the flow of carbon among the Earth's system components?

Human activities, particularly since the Industrial Revolution, have led to a rapid increase in fossil fuel use and significant land use changes, resulting in the release of approximately nine gigatons of carbon each year from the geosphere and altering the natural carbon exchange between the different spheres.

What would be necessary to halt the increase of carbon in the atmosphere according to the script?

To halt the increase of carbon in the atmosphere, we would either need to reduce human production of carbon by about half or find ways to increase the uptake of carbon in other Earth system components.