Oxygen reacted with the ammonia and methane

1. The Atmosphere 4000 Million Years ago • NO Oxygen • Carbon Dioxide • Nitrogen and water vapour • Small amounts of methane and ammonia. • The Atmosphere 3800 million years ago • Most water Vapour lost • Carbon Dioxide levels start to drop • Carbonates form layers of sediment on the sea bed Earth COOLED. Water CONDENSED and fell as rain forming oceans. CO2 dissolves in oceans so the levels dropped. Volcanoes poured out lava and gases, these formed the earths atmosphere Scientist are not sure how life began. But the first living things (green plants and algae) took CO2 from atmosphere and released OXYGEN Marine animals also form. When plants and animals die and fall to the ocean floor, buried under layers of sediment, get compressed and form fossil fuels PHOTOSYNTHESIS Carbon dioxide + Water -> Sugar + Oxygen Oxygen reacted with the ammonia and methane Most of the Carbon Dioxide gets locked in fossil fuels (COG) and sedimentary rock Methane + Oxygen -> Carbon Dioxide + water Ammonia + Oxygen -> Nitrogen + Water • The Atmosphere Today • 21% Oxygen • 78% Nitrogen • 1% Other Gases • Small amount of CO2 Plankton – crude oil and gas Plants – coal Shells and skeletons - limestone • The Atmosphere 2200 Million years ago • Slow increase in Oxygen levels • Nitrogen levels increase • Carbon dioxide levels falling slowly

2. Burning fossil fuels carbon dioxide + + fossil fuels oxygen -> water Global warming & climate change 2. Earth’s surface radiates longer wavelength heat back out to space. The graph below shows how the earth’s temperature has increased over the past 100 years. This could be because of more pollution from factories and cars. Human factors like deforestation, more agriculture and more landfill. Combustion (burning) of fossil fuels (coal, oil, gas) produces carbon dioxide and sulphur dioxide. Both gases have devastating effect. 3. Green house gases radiate this heat in all directions, including back to Earth. 1. Energy from the sun (shorter wavelengths) passes through the atmosphere. Greater use of fossil fuels releases more CO2, deforestation means less green plants to use the CO2, farm animals produce methane, more land fill is creating CO2 from decomposition means there is more carbon dioxide in the atmosphere. This leads to global warming. Global warming causes climate change. It also has effects such as melting icecaps, which effect polar bear populations, rising sea levels and increased coastal erosion. Changes in the temperature profile will change wind rainfall patterns and storms. This will affect food, water and distribution of species. Temperature and CO2 level have the same patterns over time. Carbon dioxide is a green house gas Green house gases like CO2 , methane and water vapour create the green house effect, by trapping heat and causing the earths temperature to rise. Evidence for climate change has been peer reviewed and so is reliable. As there are lots of variables, predictions are complex and so media reports can speculate and be biased.

3. Carbon footprint is a measure of the amount of CO2 and methane produced over the lifecycle of something, and so is very difficult to measure (lots of factors, like all the parts used to make something, making it, using it and disposing of it. It is easier to reduce the amount of CO2 and methane produced Reducing the Carbon Footprint Alternative technologies need to be more efficient and reduce CO2 more. Countries need to ensure any changes do not adversely affect economic growth and well being of the populations. International agreements are difficult. Some do not want to sacrifice economic development. Major changes will need global agreement. Individuals need to change their lifestyles and they may not want to. CO2 CH4 CO2 CO2 CO2 CH4

4. Burning fossil fuels Sulphur dioxide causes acid rain 1. When fossil fuels are burnt they release Sulphur Dioxide (SO2) Combustion (burning) of fossil fuels (coal, oil, gas) produces carbon dioxide and sulphur dioxide. Both gases have devastating effect. 2. This SO2 reacts with the water and oxygen in the air to form Sulphuric Acid H2SO4 (acid rain) When fuel is burned in a car, not only is carbon dioxide produced (main greenhouse gas), but also carbon monoxide (incomplete combustion, not enough oxygen) and soot (carbon particles). Effects of acid rain Damages limestone buildings Strips trees Water toxic so kills fish Sulfur impurities can be removed from fuel before it is burned (petrol, diesel, gas) or is also removed from the waste gases (coal) Carbon monoxide (CO), colourless, odourless, toxic. Binds better to red blood cells than oxygen does, so these cells carry CO instead of O2. Drowsy, unconsciousness, death. Fuel at high temperature e.g. car, can cause nitrogen to react with oxygen, forming nitrous oxides (oxides of nitrogen). These are toxic, can trigger asthma and also causes acid rain. Diesel cars burn hydrocarbons with longer chains, and so do not always completely combust. Carbon and unburned fuel are also produced. These particulates can reach the upper atmosphere, where they can reflect sunlight, causing global dimming. Global dimming can also be caused by smog (a mixture of smoke and fog), blocking sunlight