The are not equivalent. And it's fucking retarded to assume they are for a very simple reason.

The shape of the Earth is something that anyone today yesterday or tomorrow can check for themselves. You can do the same experiments that have been done for thousands of years. They are in no way shape or form reliant on past evidence. If all the writings records and evidence of the past disappeared tomorrow it would be pedestrian to reestablish the roundness of the earth with a simple self contained experiment.

Anthropogenic climate change is different because in order to establish it it does require you to compare current measurements with historical measurements. And you can't "re take" historical measurements. So no individual can in and of themselves establish this without referring to a wider scientific body which opens up far more questions for legitimacy accuracy and motive than a simple experiment to prove the shape of the Earth where all these factors can easily be removed and the experiment redone by literally anyone with any motivation.

This is not an argument for saying that the evidence we do have is necessarily false. But comparing the two issues as if they are the same is beyond retarded and betrays an utter lack of any sort of critical thought. One can just stick pole in the ground and measure it's shadow for themselves. One cannot simply measure the temperature in 1850 and compare that with the temperature today.