Volcanic activity reacted with oxygen to produce water vapour and nitrogen gas. Small amounts of methane was produced.
Bacteria from volcanoes broke down ammonia and produced nitrogen.
To form the oceans when the earth cooled steam in the atmosphere condensed into water vapour then into liquid water. This fell as rain and oceans are formed.
3.4 billion years ago life in the ocean formed and these organisms synthesised to produce oxygen.
The oxygen found its way into the atmosphere and converted into the ozone forming the ozone layer in the upper atmosphere.
Green plants and algae produce oxygen through photosynthesis
Photosynthesis = Carbon dioxide + Water -> Glucose + Oxygen
Oxygen levels in the atmosphere built up over time so more complex life (like animals) could evolve.
Algae first produced oxygen2.7 billion years ago. Over the next billion years plants evolved and the percentage of oxygen gradually increased to a level that enabled animals to evolve.
Photosynthesis = 6CO2 + 6H2O -> C6H12O6 + 6O2
The early atmosphere was mostly carbon dioxide with no oxygen like Mars and Venus.
Some of the carbon dioxide in the atmosphere dissolved in the oceans.
Algae and plantsdecreased the percentage of carbon dioxide in the atmosphere by photosynthesis.
Carbon dioxide was also decreased by the formation of sedimentary rocks and fossil fuels that contain carbon.
Simple aquatic life (marine animals) shells and skeletons contain carbonates from the oceans.
Some carbon of organisms taken in from the atmosphere and oceans became locked up in rocks and fossil fuels after the organisms died.
When plants, plankton and marine animals die they fall to seabed and get buried by layers of sediment. Over millions of years they become compressed and form sedimentary rocks, oil and gas. It traps carbon within them helping to keep carbon dioxide in the atmosphere reduced.
Crude oil and Natural gas are formed from deposits of plankton. They form reservoirs under seabed and get trapped in rocks.
Coal is a sedimentary rock made from thick plant deposits.
Limestone is a sedimentary rock mostly made of calcium carbonate. It deposits from shells and skeletons from marine organisms.
Composition of the earth's atmosphere 4.5 Billion years ago: Carbon dioxide 92%, Oxygen 0.05%, Nitrogen 4%, Water vapour 2% and Other gases 2%
Composition of the Modern atmosphere: Carbon dioxide 0.04%, Oxygen 21%, Nitrogen 78% Water Vapour less than 0.01% and Other gases 0.06%
For 200 million years, the proportions of different gases in the atmosphere have been much the same as they are today: 4/5 (80%) Nitrogen, 1/5 (20%) Oxygen and small proportions of other gases including carbon dioxide, water vapour and noble gases.
Examples of greenhouse gases are carbon dioxide, methane and water vapour.
Greenhouse gases maintain temperatures on Earth high enough to support life.
The Greenhouse effect:
Greenhouse gases in the atmosphere trap heat and keep the earth warm - they absorb long wavelength radiation that gets reflected back off the Earth
The Earth absorbs electromagnetic radiation with short wavelength
Heat is radiated from the earth as a longer wavelength infrared radiation
The atmosphere warms up
Some forms of human activity affect the amount of greenhouse gases in the atmosphere.
Deforestation: fewer trees means less carbon dioxide is removed from the atmosphere via photosynthesis. Forests are cleared for agriculture or development.
Burning fossil fuels: carbon that was locked in fossil fuels is released by carbon dioxide.
Agriculture: more farm animals produce methane e.g cattle farming. Also an increased farming of crops e.g rice.
Creating waste: more landfill sites and more waste from agriculture means more carbon dioxide and methane was released by decomposition of waste.
An increase in average global temperature is a major cause of climate change. Evidence for this has been peer-reviewed by many scientists so that you know this is reliable.
Biased information is mainly speculated in the media.
Global temperatures could lead to:
Polar ice caps melting - causing a rise in sea levels, increased flooding and costal erosion.
Changes in rainfall patterns - may affect the ability to grow food
Frequency and severity of storms may increase.
Changes in temperature - amount of water available in a habitat may affect wild species leading to differences in their distribution.
The carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
The carbon footprint can be reduced by reducing emissions of carbon dioxide and methane.
Measuring the total carbon footprint can be really difficult because there are so many different factors to consider. It can be more expensive and planting trees takes away land that could be used to grow crops
What are two alternatives to fossil fuels for reducing carbon footprints?