9781422279236

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Changes at the End of the Earth

The heat of radiation from the sun (yellow) hits the Earth. The rise in greenhouse gases traps more and more of the reflected heat off the Earth (red).

relied on fossil fuels to run.When they burn, these fuels produce CO 2 and other greenhouse gases. Other human activity, such as raisingmore livestock andusing chemical fertilizers,also released more of those gases. During the 20th century, some researchers began to realize that temperatures were rising around the Earth as the amount of greenhouse gases increased. Human activity was increasing the greenhouse effect and creating a dangerous change in the climate.