A fact is something that is 100% verified as true.
When we apply first principles thinking we realize that most facts are either interpretations or observations. Observations can be interpreted in many ways.
We observe what the temperature is today.
We observe what was recorded for temperature yesterday.
We interpret these observations as climate change.
A lot of what is stated as fact is opinion or interpretation.
If people are willing, it should be relatively easy to agree on facts.