Topic 8.18-8.26 - Earth and atmospheric science Flashcards
How was the earth’s early atmosphere formed?
Gases produced by volcanic activity formed the Earth’s early atmosphere
Describe the Earth’s early atmosphere
The Earth’s early atmosphere contained little or no oxygen, a large amount of carbon dioxide, water vapour and small amounts of other gases
How were oceans formed?
By the condensation of water vapour (after the Earth’s surface cooled to less than 100℃)
What was a result of oceans forming?
The amount of carbon dioxide in the atmosphere was decreased because carbon dioxide dissolved as the oceans formed
Explain how primitive plants grew and what their growth resulted in
The growth of primitive plants used carbon dioxide and released oxygen by photosynthesis. Consequently, the amount of oxygen in the atmosphere gradually increased.
Describe the chemical test for oxygen
Insert a glowing splint into a test tube of a gas. If the splint relights there is oxygen in the test tube
Describe the greenhouse effect
-Electromagnetic radiation at most wavelengths passes through the Earth’s atmosphere
-The Earth absorbs most of the radiation and warms up
-The earth radiates energy as infrared radiation
-Some of the infrared radiation is absorbed by various gases in the atmosphere, including CO₂, CH₄ and water vapour
-This causes the lower atmosphere to warm up
What is the evidence for human activity causing climate change?
-There is correlation between the change in atmospheric carbon dioxide concentration, global average temperature change and the consumption of fossil fuels
What is the evidence against human activity causing climate change?
Historical data is less accurate than current data due to the lack of accurate instrumentation and methods.
Fewer locations would also have been measured due to lack of satellites and transport
What human activity may cause increased levels of carbon dioxide and methane in the atmosphere?
-Burning fossil fuels (produces carbon dioxide)
-Livestock farming (e.g. cows produce methane)
+ driving, deforestation and consuming electricity produce carbon dioxide
Describe the potential effects on the climate of increased levels of carbon dioxide and methane generated by human activity
It contributes to the greenhouse effect, causing climate change.
This results in:
-Glaciers and ice melting (leading to sea levels rising)
-Seawater warming up and expanding (leading to sea levels rising)
-Rainfall changing - producing floods or droughts
-Habitats changing
Describe how the potential effects on the climate of increase levels of carbon dioxide and methane could be mitigated
-Reducing carbon dioxide output by using renewable energy sources such as wind and solar
-International treaties aimed at reducing emissions of carbon dioxide
-Building flood defences
-Building irrigation systems to provide water in droughts
-Planting different crops, better adapted to a new climate
What are the drawbacks to steps aimed at mitigating the potential effects of climate change?
-These steps are expensive, need to be on a large scale and may themselves harm the environment (e.g. production of energy for electric cars may produce carbon dioxide)
-Even if emissions fell significantly, it would take a long time for the Earth’s temperature to stabilise and then decrease
