C13 - The Earths At Flashcards
What do greenhouse gases do ? And what are the main greenhouse gases ?
Greenhouse gases in the atmosphere maintain temperatures on Earth high enough to support life.
Water vapour (H2O) , carbon dioxide (CO2) , methane (CH4)
What do greenhouses do ?
▪Greenhouses allow short-wavelength radiation from the Sun through
▪But the glass absorbs the long-wavelength radiation emitted from inside the greenhouse
▪This keeps the plants inside the greenhouse warm.
Whats the greenhouse effect ?
- The Sun emits short- wavelength radiation e.g. ultraviolet light, which warms the Earth
- The Earth loses heat by emitting long- wavelength radiation e.g. thermal infrared.
- Greenhouse gases absorb some of the long-wavelength radiation
- They re-radiate this thermal radiation in all directions, including back to Earth. This warms the atmosphere.
What are the positives and negatives of the greenhouse effect ?
▪Without the greenhouse effect, Earth would be too cold to support life.
▪But humans are increasing the levels of greenhouse gases in the atmosphere, which is warming the Earth too much.
How do human activities increase the amounts of Carbon Dioxide ?
- Deforestation: fewer trees means less CO2 is removed from the atmosphere via photosynthesis
- Burning fossil fuels: carbon that was ‘locked up’ in these fuels is released as CO2
How do human activities increase the amounts of Methane ?
- Agriculture: more farm animals produce more methane through their digestive processes.
- Creating waste: more landfill sites and more waste from agriculture means more CO2 and methane released by decomposition of waste.
What does the peer-review process do ?
The peer-review process stops scientists publishing opinions rather than hard evidence
What are the effects of climate change ?
1)An increase in global temperature could lead to polar ice caps melting - causing a rise in sea levels, increased flooding in coastal areas and coastal erosion.
2) Changes in rainfall patterns (the amount, timing and distribution) may cause some regions to get too much or too little water. This, along with changes in temperature, may affect the ability of certain regions to produce food.
3) The frequency and severity of storms may also increase.
4) Changes in temperature and the amount of water available in a habitat may affect wild species, leading to differences in their distribution.
What are carbon footprints and how are they easy to measure ?
Carbon footprints are basically a measure of the amount of carbon dioxide and other greenhouse gases released over the full life cycle of something. That can be a service (e.g. the school bus), an event (e.g. the Olympics), a product (e.g. a toastie maker) - almost anything.
2) Measuring the total carbon footprint of something can be really hard, though - or even impossible.
3) That’s because there are so many different factors to consider - for example, you would have to count the emissions released as a result of sourcing all the parts of your toastie maker and in making it, not to mention the emissions produced when you actually use it and finally dispose of it.
4) Still, a rough calculation can give a good idea of what the worst emitters are - so that people can avoid them in the future.
How can you reduce the carbon footprint ?
- Renewable energy sources or nuclear energy could be used instead of fossil fuels.
- Using more efficient processes could conserve energy and out waste. Lots of waste decomposes to release methane, so this will reduce methane emissions.
- Governments could tax companies or individuals based on the amount of greenhouse gases they emit - e.g. taxing cars based on the amount of carbon dioxide they emit over a set distance could mean that people choose to buy ones that are more fuel-efficient and so less polluting.
- Governments can also put a cap on emissions of all greenhouse gases that companies make - then sell licences for emissions up to that cap.
- There’s also technology that captures the CO, produced by burning fossil fuels before it’s released into the atmosphere - it can then be stored deep underground in cracks in the rock such as old oil wells.
Why is making reductions in your carbon footprint difficult ?
A lot of governments are also worried that making these changes will impact on the economic growth of communities - which could be bad for people’s well-being. This is particularly important for countries that are still developing.
Because not everyone is on board, it’s hard to make international agreements to reduce emissions. Most countries don’t want to sacrifice their economic development if they think that others won’t do the same.
It’s not just governments, though - individuals in developed countries need to make changes to their lifestules. But it might be hard to get people to make changes if they don’t want to and if there isn’t enough education provided about why the changes are necessary and how to make them
What is complete combustion ?
Fossil fuels, such as crude oil and coal, contain hydrocarbons.
During combustion, the carbon and hydrogen in these compounds are oxidised so that carbon dioxide and water vapour are released into the atmosphere.
When there’s plenty of oxygen, all the fuel burns - this is called complete combustion.
What is incomplete combustion ?
If there’s not enoush oxygen, some of the fuel doesn’t burn - this is called incomplete combustion.
Under these conditions, solid particles (called particulates) of soot (carbon) and unburnt fuel are released and carbon monoxide can be produced as well as carbon dioxide.
How can Particluates in the air cause problmems ? What sort of problems do they cause ?
• If particulates are inhaled, they can get stuck in the lungs and cause damage. This can then lead to respiratory problems.
• They’re also bad for the environment - they themselves, or the clouds they help to produce, reflect sunlight back into space. This means that less licht reaches the Earth - causing global dimming.
How is carbon monoxide bad for you ?
- Carbon monoxide (CO) is really dangerous because it can stop your blood from doing its proper job of carrying oxygen around the body.
- It does this by binding to the hamoglobin in your blood that normally carries 0, - so less oxygen is able to be transported round your body.
- A lack of oxygen in the blood can lead to fainting, a coma or even death.
- Carbon monoxide doesn’t have any colour or smell, so it’s very hard to detect. This makes it even more dangerous.
