Topic 9 Atomosphere Flashcards
What gases made up the Earth’s early atmosphere?
Mostly carbon dioxide, with little or no oxygen, plus nitrogen, water vapour, methane, and ammonia.
What caused the early atmosphere to form?
Intense volcanic activity released gases like CO₂, water vapour, and nitrogen.
: How did oceans form on Earth?
Water vapour in the atmosphere condensed as the Earth cooled, forming liquid water and oceans.
How did oceans reduce the amount of carbon dioxide in the atmosphere?
CO₂ dissolved in the oceans and formed carbonates, which were deposited as sediments.
How did photosynthesis change the atmosphere?
Early algae and plants used CO₂ and released O₂, increasing oxygen levels.
What are the main gases in the modern atmosphere?
78% nitrogen, 21% oxygen, <1% other gases (including CO₂, argon, and water vapour).
What role did marine organisms play in reducing CO₂?
Marine organisms used CO₂ to form calcium carbonate shells, which became limestone after they died.
What are fossil fuels made from?
Remains of plants and animals buried under sediments and compressed over millions of years.
Why did nitrogen levels in the atmosphere increase?
Volcanic activity released nitrogen, which built up because it is unreactive.
What is the link between atmospheric changes and life on Earth?
The evolution of photosynthesising organisms changed gas levels, allowing complex life to develop.
: How did crude oil and natural gas form?
From plant material buried in swamps, compressed over millions of years in absence of oxygen.
What is the role of sedimentary rocks like limestone in the carbon cycle?
They lock up carbon from dead marine organisms, reducing atmospheric CO₂.
How did coal form?
From plant material buried in swamps, compressed over millions of years in absence of oxygen.
What are the main greenhouse gases?
Carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O).
What do greenhouse gases do in the atmosphere?
They absorb outgoing infrared radiation, keeping the Earth warm – known as the greenhouse effect.
What is the greenhouse effect?
It’s the process where greenhouse gases trap heat in the atmosphere, maintaining Earth’s temperature.
How does human activity increase carbon dioxide levels?
Through burning fossil fuels (coal, oil, gas) and deforestation.
How does human activity increase methane levels?
From landfills, cattle farming, and rice fields.
What is global warming?
A gradual increase in Earth’s average temperature due to more greenhouse gases.
What are potential effects of climate change?
Melting ice caps, rising sea levels, extreme weather, habitat loss, and reduced crop yields.
Why is climate change difficult to fully understand?
Because the climate is complex, and many factors and feedback systems are involved.
What is a carbon footprint?
The total amount of greenhouse gases released by an individual, product, or activity over its lifetime.
How can we reduce carbon footprints?
Use renewable energy, improve energy efficiency, reduce waste, and plant more trees.
Why is reducing greenhouse gas emissions challenging?
It can be costly, affect economic growth, and needs global cooperation.
What is a carbon footprint?
The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service, or activity.
What contributes to a carbon footprint?
Emissions from production, transport, usage, and disposal of goods/services.
Give examples of things that have a carbon footprint.
Cars, food, electricity use, buildings, clothes, and even emails.
How can individuals reduce their carbon footprint?
Use public transport or cycle
Eat less meat and dairy
Use energy-efficient appliances
Reduce, reuse, recycle
How can businesses reduce carbon footprints?
Use renewable energy
Improve energy efficiency
Offset emissions with carbon capture or planting trees
What is carbon offsetting?
Compensating for emissions by investing in projects like reforestation or renewables.
Why is reducing carbon footprints challenging?
Can be expensive
Requires lifestyle and policy changes
Needs global cooperation
What are the main pollutants from burning fossil fuels?
Carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen oxides (NOₓ), carbon particulates, and unburnt hydrocarbons.
How is carbon monoxide (CO) formed?
From incomplete combustion of fossil fuels (not enough oxygen).
Why is carbon monoxide dangerous?
It is toxic, colorless, and odorless—it binds to hemoglobin, reducing oxygen transport in the blood.
What are particulates?
Tiny solid particles, like soot, released during incomplete combustion.
Why are particulates harmful?
Cause respiratory problems
Contribute to global dimming by reflecting sunlight
How is sulfur dioxide (SO₂) formed?
When sulfur in fuels burns (e.g., in coal).
What are the effects of sulfur dioxide?
Causes acid rain and respiratory problems.
How are nitrogen oxides (NOₓ) formed?
From high temperatures in engines causing nitrogen and oxygen from the air to react.
What are the effects of nitrogen oxides?
Cause acid rain and respiratory issues like asthma.
What is acid rain?
Rain containing dissolved sulfur dioxide or nitrogen oxides, making it acidic.
What are the effects of acid rain?
Damages buildings and statues
Harms plants and aquatic life
Erodes soil quality
What is the greenhouse effect?
The process by which greenhouse gases trap heat in the Earth’s atmosphere, keeping the planet warm.
What type of radiation comes from the Sun?
Short wavelength radiation (mainly visible light and UV).
What happens to the Sun’s radiation when it reaches Earth?
Some is reflected, but most is absorbed, warming the Earth’s surface.
What does the Earth emit after absorbing energy?
Long wavelength infrared radiation (heat).
How do greenhouse gases affect infrared radiation?
They absorb the infrared radiation and re-radiate it in all directions, including back toward Earth.
What is the result of the greenhouse effect?
The Earth’s surface stays warmer than it would without an atmosphere.
Name 3 main greenhouse gases.
Carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O).
Is the greenhouse effect natural or man-made?
It is natural and necessary for life, but human activity is enhancing it, causing global warming.
: What is the enhanced greenhouse effect?
The increase in greenhouse gases due to human activity, causing more heat to be trapped.
Why is too much greenhouse effect a problem?
It leads to climate change, including rising global temperatures and extreme weather.
