4.12 - 4.18B - Human influences on the Environment Flashcards
What air the sources of air pollution and their causes?
What is a greenhouse gas?
A greenhouse gas is a gas that absorbs infrared radiation from the Sun so it remains trapped in the Earth’s atmosphere
This is important to ensure Earth is warm enough for life, however if levels of these gases in the atmosphere increase it leads to an increase in the greenhouse effect which causes the Earth’s average temperature to rise
There are many greenhouse gases, the most important are:
Water vapour
Carbon dioxide
Methane
Nitrous oxides
CFCs
What human activities contribute to Greenhouse gases?
Human activities have led to increasing levels of carbon dioxide and methane in the atmosphere:
Carbon dioxide is produced during the combustion of fossil fuel
Methane is produced by cattle as they digest grass and released by rice paddy fields
What is the greenhouse effect process?
The Sun emits rays that enter the Earth’s atmosphere
The heat bounces back from the Earth’s surface
Some heat is reflected back out into space
Some heat is absorbed by greenhouse gases and is trapped within the Earth’s atmosphere – this is normal
However, as the levels of greenhouse gases in the atmosphere rise due to human activities the Earth’s average temperature rises beyond normal (an enhanced greenhouse effect), causing global warming
What are the consequences of global warming?
Ocean temperatures increasing, causing melting of polar ice caps / rising sea levels / flooding / coral bleaching
Increasing temperatures causing extreme weather like super storms, flooding, droughts
Changes in or loss of habitats due to these extreme weather events
Decreases in biodiversity as food chains are disrupted and extinction rates increase
Increases in migration of species to new places, including increased spread of pests and disease
What is the evidence for global warming?
There is scientific consensus (almost all scientists agree) that global warming is happening and that human activities are largely responsible for the most recent warming
This scientific consensus is based on systematic reviews of thousands of scientific research papers that have been ‘peer reviewed’ by other scientists (the method used by scientists to check each other’s work in order to ensure that research findings are valid)
Although they can make good predictions, it is difficult for scientists to say for certain what the consequences of global warming will be
What are the Biological consequences of water pollution by sewage?
What are the Biological consequences of Eutrophication?
What is deforestation?
Deforestation is the clearing of trees (usually on a large scale)
If trees are replaced by replanting it can be a sustainable practise
Generally the trees are being cleared for the land to be used in a different way (for building, grazing for cattle, planting of monocultures such as palm oil plantations etc) and therefore it is not sustainable
What are the consequences of deforestation?
What are more consequences of deforestation?
