> Temperature variations in ancient times are very unreliable, because they can only be inferred indirectly > The big giveaway for anthropogenic climate change

> Temperature variations in ancient times are very unreliable, because they can only be inferred indirectly > The big giveaway for anthropogenic climate change is co2 concentration, since we can directly measure its value hundreds of thousands of years in the past thanks to air bubbles enclosed deep in glaciers I can't believe that these two are consecutive sentences. Are you manipulating the meaning of "direct measurement" on purpose? You can't really get a direct measurement of something from the past without a time machine. Glaciers are, by definition, an indirect measurement, that relies on a specific model to calculate the measurement value. There is a lot of criticism of this model from chemists, but since it is no longer a scientific discussion, but a political one, these people typically get repressed.