Identify the main concepts in this paragraph.
1. Global warming
2. Increase
3. Earth's temperature
4. Greenhouse gases
5. Buildup
6. Atmosphere
Global warming is an increase in the earth’s overall temperature caused by a buildup of greenhouse gases in the atmosphere.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

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

### Input:
Global warming is an increase in the earth’s overall temperature caused by a buildup of greenhouse gases in the atmosphere.

### Response:
1. Global warming
2. Increase
3. Earth's temperature
4. Greenhouse gases
5. Buildup
6. Atmosphere