C9: The atmosphere UNFINISHED Flashcards
(26 cards)
What gases are the in the atmosphere today:
- 78% nitrogen
- 21% oxygen
- A small amount of other gases (eg. noble gases, water vapour)
Describe the early atmosphere? (4)
- Intense volcanic activity
- This released water vapour which condensed to form the oceans
- Carbon dioxide was also released, so the atmosphere was mainly carbon dioxide, with very little oxygen.
- Volcanoes also released small amounts of other gases, eg. ammonia, methane and nitrogen which built up over time.
Describe the differences between the early atmosphere and the atmosphere now. (3)
- Carbon dioxide: used to made up nearly all of the atmosphere, but now only makes up a tiny amount.
- Nitrogen: used to be very tiny amounts but now makes up 78%.
- Oxygen: used to contain a very small amount, but now makes up 21%
Why did the carbon dioxide in the atmosphere fall? (4)
- Carbon dioxide dissolved in oceans to form weak acid. This reacted with minerals to form precipitates. These formed sedimented carbonate rock on the sea bed.
- Other CO2 was used to make corals and shells. When they died, they make limestone.
- Photosynthesis form algae and plants.
- All this reduced the amount of CO2 in the atmosphere.
Why did the levels of oxygen increase? (2)
- Plants and algae evolved. Photosynthesis created oxygen.
- This meant animals could evolve.
How is coal formed?
Ferns and trees die. If they die in a marsh, (with no oxygen), then no bacteria can carry out decomposition. Over time, the pressure and temperatures from layers of sediment form coal.
How is crude oil formed?
- Plankton die and fall to the sea bed. If no oxygen is present, they will no decompose. Heat and pressure from sediment covert them to crude oil.
How is natural gas formed, and what is it made of?
- Mainly the hydrocarbon methane
- Find it near oil deposits because it’s formed in a similar way.
Name a greenhouse gas:
Any one from:
Methane, carbon dioxide, water vapour
Describe the greenhouse effect
- Radiation travels from the sun as short length radiation (eg. ultra-violet, visible light)
- Some is reflected back into space but most passes through the atmosphere, because it can weave through the gas molecules in the atmosphere more easily.
- The energy is absorbed.
- It is then released as long wave radiation, and some of it is absorbed by the gas particles in the atmosphere.
- This causes the temperature of the atmosphere to increase.
Why is the greenhouse important?
- It keeps the earth warm enough to support life.
why is carbon dioxide in the atmosphere increasing?
- Burning fossil fuels (eg. coal for electricity)
- Its usually absorbed by trees, but deforestation is stopping this
- Burning forests believes more carbon dioxide
Why is methane increasing in the atmosphere?
- Released during agriculture (crops and cattle)
How are increasing levels of methane and Carbon dioxide affecting the atmosphere?
Becoming hotter as more energy from the sun is trapped
Effects of climate change:
- Melting ice caps, rising sea levels, more flooding
- Sever weather eg. more storms
- Change distribution of animals eg. insects. Would lead to changing distribution of insect-borne diseases like malaria.
What do scientists believe about climate change and why?
- Human activity is the main cause
- Been shared between different scientists, peer review.
What is peer review?
Scientists share their findings and others can critise it to stop false claims eg. based on poor evidence or bias
What are problems with climate change? (2)
- It is complicated, so that can lead to biased or oversimplified claims in the media. Scientists must work harder to communicate the ideas around climate change to the general public.
- There is uncertainty eg. around exactly how much temperatures will increase by, leading to speculation in the media.
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 event.
What does a carbon footprint aim to do?
Give us an idea of how much something contributes to climate change
How can we reduce carbon emissions? (4)
- Insulate our homes, or turn the heating down
- Use public transport (less CO2 per passenger)
- Switch to renewable sources of energy eg. wind power
- Reduce amount of energy we use at hom eg. energy saving lightbulbs
What are the problems with the ways we can reduce carbon emissions? (2)
- Expensive, people are reluctant to pay
- Inconvenient
How can we reduce methane emissions? And what is the problem with this? (2 of each)
- Eat less beef and dairy products
- People enjoy them and are unlikely to change their diets
- Trapping methane from landfills and burning it to produce electricity
- This is expensive
What is a fuel?
Something that releases energy when combusted (burned). Eg. coal and hydrocarbons
