The Atmosphere 4000 Million Years ago NO Oxygen

The Atmosphere 4000 Million Years ago • NO Oxygen • Carbon Dioxide • Nitrogen and water vapour • Small amounts of methane and ammonia. Earth COOLED. Water CONDENSED and fell as rain forming oceans. CO 2 dissolves in oceans so the levels dropped. 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 Volcanoes poured out lava and gases, these formed the earths atmosphere 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 Oxygen reacted with the ammonia and methane PHOTOSYNTHESIS Carbon dioxide + Water -> Sugar + Oxygen Mo Dio st of fos xide the C sed sil fu gets arbo im els lock n ( en tar COG ed in y r ) an ock d Methane + Oxygen -> Carbon Dioxide + water Ammonia + Oxygen -> Nitrogen + Water The Atmosphere 2200 Million years ago • Slow increase in Oxygen levels • Nitrogen levels increase • Carbon dioxide levels falling slowly Scientist are not sure how life began. But the first living things (green plants and algae) took CO 2 from atmosphere and released OXYGEN Plankton – crude oil and gas Plants – coal Shells and skeletons - limestone The Atmosphere Today • 21% Oxygen • 78% Nitrogen • 1% Other Gases • Small amount of CO 2

Burning fossil fuels Combustion (burning) of fossil fuels (coal, oil, gas) produces carbon dioxide and sulphur dioxide. Both gases have devastating effect. fossil fuels oxygen -> carbon dioxide + + water Global warming & climate change below shows how the The graph 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. Greater use of fossil fuels releases more CO 2, deforestation means less green plants to use the CO 2, farm animals produce methane, more land fill is creating CO 2 from decomposition means there is more carbon dioxide in the Global warming causes atmosphere. This leads to global warming. Carbon dioxide is a green house gas Green house gases like CO 2 , methane and water vapour create the green house effect, by trapping heat and causing the earths temperature to rise. 2. Earth’s surface radiates longer wavelength heat back out to space. 1. Energy from the sun (shorter wavelengths) passes through the atmosphere. 3. Green house gases radiate this heat in all directions, including back to Earth. 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 CO 2 level have the same patterns over time. 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.

Reducing the Carbon Footprint Alternative technologies need to be more efficient and reduce CO 2 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 Capturing CO 2 development. produced in Major changes will need power stations global agreement. and storing it Individuals need to in rocks change their lifestyles and they may not CO 2 want to. Using biofuels (plant products burnt as fuel) CO 2 Carbon footprint is a measure of the amount of CO 2 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 CO 2 and methane produced Using nuclear and renewable energy sources and not fossil fuels CO 2 Eating less beef CH 4 CO 2 Charging more tax on polluting vehicles and companies Sending less waste to landfill by recycling more CH 4

Burning fossil fuels Sulphur dioxide causes acid rain Combustion (burning) of fossil fuels (coal, oil, gas) produces carbon dioxide and sulphur dioxide. Both gases have devastating effect. 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). Carbon monoxide (CO), colourless, odourless, toxic. Binds better to red blood cells than oxygen does, so these cells carry CO instead of O 2. Drowsy, unconsciousness, death. 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. 1. When fossil fuels are burnt they release Sulphur Dioxide (SO 2) 2. This SO 2 reacts with the water and oxygen in the air to form Sulphuric Acid H 2 SO 4 (acid rain) 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) 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. Global dimming can also be caused by smog (a mixture of smoke and fog), blocking sunlight