climate change and greenhouse gases

• greenhouse gases act like a...

  insulating layer in Earth's atmosphere
• greenhouse gas examples


  carbon dioxide, methane, water vapor
• all particles absorb...


  certain frequencies of radiation
• what radiation does greenhouse gases absorb?

  they don't absorb the incoming short wavelength radiation from the Sun - but they do absorb the long wavelength radiation that gets reflected back off the Earth
• what happens to the radiation that greenhouse gases absorb?

  they re-radiate it in all directions - including back towards Earth
• the longwave radiation is ... radiation

  thermal

  - this results in warming of the surface of the Earth
• what is the greenhouse effect?

  the process by which gases hold heat in the atmosphere
• how is the greenhouse effect responsible for warming the surface of the Earth?

  short wavelength radiation from the sun passes through the Earth's atmosphere. it hits the Earth's surface and is reflected back as long wavelength radiation. this long wavelength radiation is absorbed by greenhouse gases in the atmosphere. they re-radiate it in all directions, including back towards the Earth, warming its surface
• examples of human activity that affect the amount of greenhouse gases in the atmosphere

  - deforestation (fewer trees means less CO2 is removed from the atmosphere via photosynthesis

  - burning fossil fuels (carbon that was 'trapped) in these fuels is released as CO2

  - 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 would happen without greenhouse gases?

  the earth would be too cold for water to be a liquid and would not be able to support life as the heat emitted by the Earth would simply pass outwards from the Earth's surface into space
• increasing carbon dioxide is linked to...

  climate change
• earth's temperature varies...


  naturally
• increasing global temperature will lead to...

  climate change
• climate change


  a change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels
• causes of climate change

  - increased concentration of CO2

  - burning fossil fuels in cars, industry and homes

  - deforestation

  - burning of forests
• climate change effects


  - rising temperatures

  - changes in weather patterns

  - melting ice and glaciers

  - loss of biodiversity

  - changing ocean currents
• climate change impacts


  - crops failing

  - mountain glaciers disappearing

  - threatening water sources/sea levels in some areas

  - extensive damage to coral reefs leads to extinction of species

  - rising intensity of storms and natural disasters
• how are carbon dioxide levels increasing?

  mostly because of the fossil fuels that people are burning for energy
• how are methane levels increasing?

  agriculture, fossil fuels, and decomposition of landfill waste
• consequences of climate change

  melting ice caps, rising sea levels, extreme weather, drought, increased extinction rates, tropical diseases, change of distribution of animals
• carbon footprint


  the total carbon dioxide emissions produced by an individual, group, product, service, event or location
• why is measuring carbon footprint hard?

  because there are many different factors to consider, such as the insufficient knowledge about all contributing factors, and the complexity of all processes including the natural ones.
• ways to reduce carbon footprint

  - renewable energy sources or nuclear energy instead of fossil fuels

  - using more efficient processes could conserve energy and cut waste

  - governments could tax companies or individuals based on the amount of greenhouse gases they emit

  - governments can also put a cap on emissions of all greenhouse gas that companies make

  - they could use technology that captures the CO2 produced by burning fossil fuels
• why would it be difficult to reduce carbon footprint?

  - carbon capture and storage is a relatively new idea and still at the development stage

  - many renewable energy technologies, e.g. solar panels, are still quite expensive

  - making changes may impact some countries' economic growth and well-being of its citizens
• how can people reduce their carbon footprint?

  - choosing to cycle or walk instead of using a car

  - reducing how much they air travel

  - doing anything that saves energy at home (e.g. turning heating down)
• why is it difficult to get people to reduce their carbon footprint?

  - some may just not want to

  - there may not be enough education provided about why changes are necessary and how to make them
• fossil fuels


  a natural fuel such as coal or gas, formed in the geological past from the remains of living organisms and are non-renewable
• combustion of fossil fuels releases...

  gases and particles
• fossil fuels contain...

  hydrocarbons - during combustion, the carbon and hydrogen in these compounds are oxidised, so that carbon dioxide and water vapour are released back into the atmosphere
• coal


  a fossil fuel that forms underground from partially decomposed plant material
• crude oil


  fossil fuel that is made of organisms that lived and died millions of years ago - mainly plankton that was buried in mud
• natural gas


  a gas with high methane content, found along with various fossil fuels and is used as a fuel.
• all fossil fuels contain trapped...

  carbon
• complete combustion


  combustion that occurs when there is plenty of oxygen; it produces carbon dioxide and water vapour
• incomplete combustion


  when a fuel burns in insufficient oxygen, producing carbon monoxide as a toxic product. solid particles (called particulates), made up of soot (carbon) and unburned hydrocarbons, are released
• what problems do particles in the air cause?

  - if particles are inhaled, they can gen stuck in the lungs and cause damage; this can then lead to respiratory problems

  - they are bad for the environment too: particulates (and the clouds they help produce) reflect sunlight back into space, meaning less light reaches the Earth (global dimming)
• what problems does carbon dioxide cause?

  global warming
• what problems does carbon monoxide cause?

  - binds to the haemoglobin in your blood that normally carries oxygen, this means less oxygen is able to be transported round your body: lack of oxygen in the blood can lead to fainting, a coma or even death

  - doesn't have any colour or smell so it is very hard to detect, making it even more dangerous
• sulfur and oxides of nitrogen can be...

  released
• sulfur dioxide is released during...

  combustion of fossil fuels (e.g. coal) that contain sulfur impurities - the sulfur in the fuel becomes oxidised