Scientists call it a human "fingerprint."
In new research, scientists took the real world numbers from 1880 to 2012.
They fed the data along with the natural and human factors that can affect climate into computer models.
These models showed a combination of the two factors explained the recent warming trend.
The results were similar to what actually happened in the real world.
When they ran the models with only the natural factors, the numbers did not add up.
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