Greenhouse gases
The gases in the atmosphere which absorb solar radiation and keep the earth warm
Global warming
A gradual increase in the overall temperature of the earth's atmosphere due to the greenhouse effect caused by an increase in greenhouse gases
Fossil fuels
These are fuels formed by natural processes like decomposition of buried dead organisms, in the absence of air
Pollution
Contamination of the environment as a result of human activities
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Deforestation
Cutting down and removing all or most of the trees in a forest