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Topic last updated: 09 Nov 2023
    • Ico Chemistry Chemistry
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    • Biology Biology
    • 14-16
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The Earth and the early Atmosphere

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The modern atmosphere and global warming

Due to human activity, the atmosphere is changing again. This is causing global warming.

Carbon dioxide is a greenhouse gas, and more of this is being added to the atmosphere, causing the greenhouse effect. Water vapour and methane are also greenhouse gases.

Greenhouse gases are mostly released from burning fossil fuels which include coal, oil and gas, or from farming. This is because farm animals release a lot of methane too.

Some of this carbon dioxide can be sequestered in oceans, lakes, plants and peat bogs, and this removes it from the atmosphere. This is important in helping to reduce global warming, but increased carbon dioxide in these natural environments can impact the organisms living in them too. This is because CO2 dissolved in sea water becomes carbonic acid (H2CO3), which damages aquatic life and makes subsequent food chain disturbances likely.

As plants and trees are carbon stores, deforestation also has an impact since trees take in carbon dioxide for photosynthesis. Therefore, when trees are cut down and burned, this releases the greenhouse gases back into the atmosphere.

The atmosphere - global warming

Humans are also destroying peat bogs to use the land for farming. Peat bogs are waterlogged ecosystems which contain partially decomposed plants in low oxygen environments. This lack of oxygen means that plants cannot fully decompose, meaning the plants inside the bogs are carbon stores. However, when the bogs are destroyed all the water is drained from them. This allows any plant material trapped inside the bogs to decompose. As they decompose, the CO2 stored in them gets released into the atmosphere and this contributes to global warming, which causes climate change. Peat is also used as compost or burned as a fuel. Gardeners can help to reduce the demand for peat by using peat free compost.

The greenhouse effect:

Below is a diagram of the greenhouse effect.

Though the greenhouse effect is required to make sure that the Earth stays warm enough for life, global warming means that it is amplified, and the Earth’s surface is getting too hot.

Usually, energy from the Sun returns to space as infrared radiation. However, greenhouse gases can absorb the infrared radiation and re-radiate it back towards the Earth. This prevents the Earth from cooling down.

The greenhouse effect KS3