Let me repeat, I am so shocked a Republican denies global warming.
Let me repeat Democrats assert they have temperature data for the huge gap when and where nobody recorded any data. And Democrats assert that "a Republican" denies global warming because without that data you don`t have a case that global warming is caused by Republican CO2 emissions.
It`s as simple as that but not simple enough for Democrats !
They can`t see the difference between natural and man made global warming.
Of course they can`t afford to acknowledge that, else they can`t use a label like "deniers"
They do that with everything where they can`t win a debate on substance, from race relations, gender equality, crime, immigration, taxation etc. And if all fails then it`s down to smearing the opponent any way they can.
No, stupid ass, Democrats do not assert that they have temperature data for the past, scientists do. Or are you implying that all scientists are Democrats? Could be correct, after all, being a scientist requires an above average intellect.
Past Climate | NOAA Climate.gov
How Do We Study Past Climates?
Paleoclimatology is the study of climate records from hundreds to millions of years ago. Information for paleoclimate studies come from natural records rather than instruments: these indirect records of climatic conditions are called proxy records.

Coring a tree to gain access to tree ring data.
Image source:
Penn State Department of Meterology
One of the most easily recognized type of paleoclimate records is tree ring data. Trees that grow a single annual ring can preserve a record of the conditions they experienced each year. Rocks deposited by glaciers are another example of proxy records. Scientists can recognize the distinctive pattern of sediments in rocks formed by glaciers. Wherever they find glacial rocks then, they know that glaciers were present in that location at some point in the past. Once they examine fossils and other clues about when the rocks were deposited, they use the information to reconstruct the climate story for that location. Other sources of proxy data for climate include lake and ocean sediments, layers of ice (cored from ice sheets), corals, fossils, and historical records from ship logs and early weather observer