Realclimate has a new
post from Stefan Rahmstorf that among other things discusses
Marcott et al. 2013.
I’ll use this as a jumping off point to what’s likely my final comment on “empirical evidence” and climate variation.
First I want to point out that the whole “give me empirical evidence that proves there is no hidden variation in the pale-climate record is back assward. Empirical evidence can never prove there is nothing hidden in the data. The data IS the empirical evidence, so things hidden in it so it can’t empirically show things that are not in it.
Importantly, in science it’s never expected to. Since it’s impossible to disprove every other possibility science uses empirical evidence to support a theory or decide between competing theories, but never to prove no competing theory is possible.
IOW unless a fully formed competing theory is proposed you don’t need to provide empirical evidence refuting it. For example “prove to me with empirical evidence that the WTC wasn’t destroyed with some heretofore unknown type of explosive” isn’t something you can truly prove. Until a real, testable alternative is proposed all you can do is show that no explosive is required to explain the collapse and that there is no evidence of explosives.
Similarly with the climate record you can show that there is no evidence for large rapid climate swings in the paleo-climate record and no known mechanism that would cause such swings. See the links at the start of this post to confirm this has been done. You can also show that should such climate swings occur they would show up in the paleo-climate record. You can see this “empirically” by verifying that volcanic eruptions do show up in the temperature record, or test it using a model (also empirical) as
Tamino does here
When there is no evidence for something, no known mechanism by which it could occur and no competing theory which can be disproved the correct skeptical and scientific position is to discount it until there is either evidence or a theory to test. You don’t need to provide empirical evidence it can’t occur, indeed there are plenty of examples of science reversing it’s view when evidence or sound theory is provided. It is, however, the responsibility of the “heretic” to provide that evidence/theory, they don’t get to just sit back and say “I want proof my idea is incorrect”.