C13. The Earth's Atmosphere Flashcards
Describe the proportions of gases in the modern atmosphere
Around 80% of N₂
20% of O₂
Small quantities of CO₂, H₂O and noble gases
Describe the Earth’s early atmosphere and how it was formed
a) The Earth was hot when it is formed
b) There was significant volcanic activity
c) Gases have been released from these volcanoes
d) These gases included CO₂, N₂,CH₄,NH₃,H₂O
How did the amount of oxygen in the atmosphere increase?
Algae and plans produced the atmospheric O₂ by photosynthesis, which can be represented by the equation: 6 CO₂ + 6 H₂O –> C₆H₁₂O₆ + 6 O₂. As the amount of gradually O₂ increased, there were more plants that produced more oxygen
How did the amount of carbon dioxide in the atmosphere decrease?
a) Some CO₂ was dissolved in the oceans, where it reacted with metal ions to form insoluble carbonates, such as CaCO₃, or was taken in by animals to become a part of skeleton. When animal dies, this becomes a sedimentary rock.
b) Some CO₂, was used in photosynthesis to make oxygen
What is the greenhouse effect? What are greenhouse gases?
Greenhouse gases in the atmosphere maintain temperature on Earth high enough to support life.
They allow short wavelength radiation from the sun to pass through the atmosphere to the Earth’s surface, but absorb the outgoing long wavelength radiation from the Earth causing an increasing in temperature
Why is the greenhouse effect necessary for life?
The greenhouse effect is a natural phenomenon. Without it, the Earth would be too cold for life to exist
How have human activities led to an increase in greenhouse gases?
carbon dioxide - combustion and deforestation
Methane - increased farming and decomposition in landfills
What are the potential effects of global climate change?
Sea level rise, which may cause flooding and increased coastal erosion
More frequent and severe storms
Changes in the amount, timing and distribution of rainfall
Temperature and water stress for humans and wildlife
Change in the food-producing capacity of some regions
Changes to the distribution of wildlife species
What is a carbon footprint?
A carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
What actions can be taken to reduce a carbon footprint?
Increased use of alternative energy supplies
Energy conservation
Carbon capture and storage
Carbon taxes and licences
Carbon off-setting including through tree planting
Carbon neutrality - zero net release
What are the problems of reducing the carbon footprint?
Scientific disagreement over causes and consequences of global climate change
Lack of public information and education
Lifestyle changes (people don’t want to give up their cars)
Economic considerations
Incomplete international cooperation
What are the advantages of complete combustion?
Less soot is made with complete combustion
More heat per gram of fuel is released with complete combustion
Poisonous carbon monoxide is not produced with complete combustion
How is pollution caused by combustion?
When a fuel burns, the gases released to the atmosphere include carbon dioxide, water vapour, carbon monoxide, sulphur dioxide and oxides of nitrogen
Solid particles and unburned hydrocarbons may also be released that form particulates in the atmosphere
What are the issues regarding sulphur dioxide and oxides of nitrogen?
Sulphur dioxide and oxides of nitrogen causes respiratory problems in humans and cause acid rain. Acid rain damages plants and buildings
What problems do particulates cause?
Particulates, such as carbon particles, cause global dimming by reducing the amount of sunlight that reaches the Earth’s surface. Particulates cause health problems for humans because of damage to the lungs
