Dialoguing with rocks

While channel surfing the other night I heard a scientist remark, "We have 700,000 years of recorded history telling us that global warming is a reality."

And on another night, on another channel, another scientist admits, "The fossil record, dating billions of years back to the Archean Eon, is unambiguous and establishes evolution as a fact."

Ok fine. Rocks are our friends and clouds are our neighbors.

But when it comes to considering first-hand accounts of events that occurred a mere 2000 years ago, why do skeptics become so suddenly herd of hearing?