there are ways to determine previous climates, atmospheric compositions and other information without having been there with scientific monitoring equipment. And that is information that has been gathered by scientists for quite some time and used to support the global warming hypothesis.

Atmospheric gases are trapped in snow & ice.... deep bores taken from polar ice packs is tested to determine atmospheric gas composition for a long geologic period. Different isotopes of carbon and oxygen in ancient ice cores is used to determine temperatures.

Trees growth is related to temperature and long lived trees can show the growth rings that resulted from temperatures over their lifetime. Fossilized trees can provide similar information.

Ancient environments left behind sediments that can be studied for evidence of what type of climate existed during its formation.

Scientists from many different disciplines have collected data that is available for all to study and view from the many points of view. When evidence from multiple sources is put together it should become harder to refute... at least in a rational fashion.

So, the thread title reveals the exasperation of those who have to put up with the willing blindness of people who ignore anything that disturbs their worldview. Who seek to discredit rather than actually investigate the evidence.