Topic 4: Climate chane in the context of Geological Time Flashcards
Describe how the climate have fluctuated since Earth was formed and how different the situation is now
The climate has been driven by different mechanisms working on different timescales (orbital cycles in thousands of years or plate tectonics in millions of years).
Now, the anthropogenic activites are changing the climate at an unprecedented rate in geological record.
How does the orbital cycles affect Earth’s climate?
The shape of orbit as well as the tilt of the Earth affect how much solar energy reaches our planet and these cycles also change every Milankovitch cycle.
If we continue destroying the environment at this rate, what will happen?
The world will face a runaway greenhouse effect and deglaciation era, in which all ice sheets will melt, rising sea level and chaning the coastline of many countries. Our world will turn into an ice-free world.
What main natural mechanisms are responsible for capturing and releasing CO2 into the atmosphere in the Deep Carbon Cycle?
What valve is it called?
- Volcanisms are responsible for pumping CO2 into the atmosphere.
- Silicate weathering captures CO2 and put it back to the core
A “two-way” carbon valve
Describe how chemical weathering captures carbon
As rain falls through atmosphere, it picks up CO2 and dissolved CO2 makes the droplets slightly acidic because of carbonic acid H2CO3.
When this interacts with rocks, CO2 is then absorbed in sediments as carbonate and bicarbonate.
These substances are also washed out to the oceans as ions, being used to build CaCO3 skeletons.
What is the role of mountain building in fostering chemical weathering?
As mountains are forming, new rocks ascend and these are more likely to react with H2CO3, thus increasing the rate of chemical weathering.
Mention some processes involve in releasing and capturing CO2.
- Subduction zone, volcanism, mantle plumes, etc. release CO2
- Weathering, biosphere involvement help capture CO2
