How did the Earth get here?
Big Bang (13.8 billion years ago)
When was the Earth formed?
4.6 billion years ago
What was the Big Bang?
an explosion
(gases and dust)
What were the gases formed from the Big Bang?
Hydrogen and helium
Describe phase 1 of how the Earth’s atmosphere developed
earth was covered in volcanoes that released gases
The early atmosphere was probably mostly co2
Volcanoes released nitrogen, co2 and water vapour
What were the 2 other gases that were given off by volcanoes in small amounts?
methane
Ammonia
Describe phase 2 of how the Earth’s atmosphere developed
Water vapour condensed to form oceans
Co2 was absorbed by the oceans, went through a series of reactions to form carbonate precipitates that formed sediment on the seabed
Green plants and algae evolved, they absorbed co2 and carried out photosynthesis
Describe phase 3 of how the Earth’s atmosphere developed
more and more co2 taken out of atmosphere
Forming rocks and crude oil
What is todays atmosphere mostly made up of?
Nitrogen and oxygen
How has carbon locked into rocks?
co2 was taken in by plants and converted into glucose and oxygen via photosynthesis
animals eat the plant carbon can be transferred to animals skeletons and shells
skeletons and shells get covered by sediment, forming sedimentary rocks eg. limestone
Remains of ancient animals were crushed by large scale movements of the Earth, and heated by Earth’s crust, forming fossil fuels and natural gas
What do greenhouse gases absorb?
Long wavelength radiation
What is the greenhouse effect?
The warming of the earths surface (thermal radiation)
Stages of the greenhouse effect?
Sun emits infrared waves which enter the atmosphere
Radiation is absorbed by the Earth
Longer wavelength radiation is emitted
Carbon dioxide stops further longer wavelength radiation escaping
What human activity affects the amount of greenhouse gases in the atmosphere?
deforestation - fewer trees = less co2 removed via photosynthesis
Burning fossil fuels - releases co2
Agriculture - cows produce methane
Land fill sites
How does climate change happen?
Average temperature of the Earth increases
Extra co2 is released due to human activity
What might happen if climate change continues?
ice caps melting = causing a rise in sea levels = increasing flooding
Droughts
Frequency of storms increase
What are carbon footprints?
A measure of how much co2 and other greenhouse gases are released
What are the ways of reducing carbon footprints?
Renewable energy sources or nuclear energy rather than fossil fuels
Tax companies based on the amount of greenhouse gases emitted
capturing carbon and storing it underground
What are the disadvantages of reducing carbon footprints?
governments worries that if they raise tax economic growth might be at risk
People’s minds are hard to change and might lack the education to understand
What are the the atmosphere pollutants?
Nitrogen oxide
Sulfur dioxide
Carbon monoxide
Carbon dioxide
particulates
What’s the difference between complete combustion and incomplete combustion?
When there’s plenty of oxygen so all fuel burns vs when there’s not enough oxygen so some fuels don’t burn
what’s carbon neutral?
products that don’t affect the the atmospheric co2 concentration
what are the problems with carbon monoxide?
colourless
odourless
means hard to detect
why does global dimming happen?
participates reflect incoming radiation into space