Higher Global Climate Change

Human Cause - Greenhouse Gases

Carbon Dioxide (CO₂)

Methane (CH₄)

Nitrous Oxides (N₂O)

Chlorofluorocarbons (CFC’s)

Hydrofluorocarbons (HFC’s)

Sulphur hexafluoride (SF₆)

There are 6 main Greenhouses gases, but the most important ones are the first three.
The amount of these gases have all been increasing in our atmosphere due to human factors.

Carbon Dioxide (CO₂)

Burning fossil fuels, for example coal, oil and natural gas release Carbon Dioxide into the atmosphere. These has been used increasingly to generate electricity in power stations and to heat homes.

Deforestation, especially in the Amazon Rainforest, has resulted in more carbon dioxide being released when trees are burnt.

With fewer trees there is less photosynthesis so less CO² is captured by vegetation.

Methane (CH₄)

21 times as effective in trapping heat than CO2.

Methane is produced when organic material is broken down anaerobically, without oxygen. This can happen in the following ways:

In landfill sites as waste / vegetation decomposes.
In padi fields when the rice plants are left to rot after they have been harvested.
In the stomachs of cows as they digest grass and then released as they belch and fart.
When permafrost melts the methane trapped in the ground for thousands of years can continue to biodegrade and is able to escape into the atmosphere.

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Nitrous Oxides (N₂O)

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310 times more effective in trapping heat than Carbon Dioxide.

The largest source is agriculture and the majority of agricultural emissions result from nitrogen fertilisers of agricultural soils (87 percent of the agriculture total). When too much nitrogen feritsier is put on the farmland it can react with the rain and atmosphere and turn into nitrous oxide.

Nitrous Oxide is also released from vehicles especially diesel cars / lorries.

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F-Gases

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SF6 - 23,500 time more potent than CO2 at trapping heat. It also lasts in the atmosphere for approx. 1000 years.

It is a cheap and non-flammable, SF6 is a colourless, odourless, synthetic gas. It makes a hugely effective insulating material for medium and high-voltage electrical installations.
It is widely used across the industry, from large power stations to wind turbines to electrical sub-stations in towns and cities. It prevents electrical accidents and fires.

SF6

Human Causes of Greenhouse Gases

Growth of the global population but mostly an increase in wealth means more people need food especially an increase in meat production. Growing demand for heating and electrical supply as well as cars and transport have also increased these gases.

Video: Human causes of climate change

Global Climate Change 2

Diagram Q2: Global air temperatures 1850—2011

Explain the human activities which have contributed to the changes in global air temperatures.
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Global Effects

Sea level rises caused by an expansion of the sea as it becomes warmer, and also by the melting of glaciers and ice caps in Greenland and Antarctica. When ice melts in the Arctic Sea it does not effect the sea level as the ice displaces the same volume of water it releases but when ice on Greenland melts it turns to water and flows into the Atlantic rising the sea levels.

Climate change: Why are sea levels rising? - CBBC Newsround

Low–lying coastal areas, e.g. Bangladesh affected with large-scale displacement of people and loss of land for farming and destruction of property

Global Effects

Impact on wildlife and natural habitats, e.g. extinction of at least 10% of land species and coral reefs suffer 80% bleaching

Climate change: What is coral bleaching? - CBBC Newsround

Global Effects

Climate change is causing permafrost warming and thawing in high latitude regions (Alaksa), this has an impact on infrastructure such as pipelines which can fracture as their foundations move as the land thaws.

As Arctic ice melts shipping could start to use the North West passage and thereby making communication links between Europe and Asia- much quicker and cheaper.

Changes to ocean current circulation, e.g. in the Atlantic the thermohaline circulation starts to lose impact on north–western Europe, resulting in considerably colder winters.