Identify the main concepts in this paragraph.
Global warming is an increase in the earth’s overall temperature caused by a buildup of greenhouse gases in the atmosphere.
Main concepts: Global warming, Earth's temperature, Greenhouse gases, Atmosphere.
Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Identify the main concepts in this paragraph.

### Response:
Main concepts: Global warming, Earth's temperature, Greenhouse gases, Atmosphere.