Scientists are skeptics. The basic premise of science is to treat all ideas, proposals, or theories as worth looking at, with skepticism. Look at the concept and compare it to what we know, what has been observed. All scientific “laws”, “theories” and “scenarios” are subject to this process.
The theories are supported to the extent that the observations agree with them — Newton’s laws, some quantum mechanics, evolution, gravity and Einstein’s laws are doing well. The ‘laws’ are simply theories that have a record of much support from data with no counter observations. Note that some theories can exist and be believed without data because they are consistent with known laws and data.
Scenarios are less substantial models, often numerical these days, that predict/extrapolate known laws using mathematical approximations. They are theories that are treated with much skepticism, which diminishes only with time and consistency with observations. The mainline GW models have made this transition, performing well in predicting the observed trends.
The data must be treated with great care, particularly when involving growth rings, isotopes, statistics and other involved scientific models. This is always done as an essential part of the scientific process, and when the vast majority of scientists who are expert in the process agree with it, the data is accepted. This must be done if ANY progress is to be made.
An element of skepticism remains, but only new improved data can invalidate or modify the data and theory. This often comes; even Newton’s and Einstein’s theories have had to do this. But it must involve BASIC data that doesn’t support the theory. A typo, an error in some example, or even a stupid omission can’t invalidate a whole work (e.g., a typo plus a wrong conjecture carried in a couple of obscure pages of an 1800 page report doesn’t invalidate the whole report!). I was disturbed by collecting about 50 errors in my 489 page math textbook, and my thesis adviser, author of several books, said “Gee, only 50, that’s quite good.”
Anyway, ‘GW skeptics’ doesn’t do it for those who don’t believe the scientists. I’m a skeptic (tho I see the odds as about 100-1 that it’s warming and Homo sapiens is helping it along). I’ll try to refer to “those who deny that GW exists, or that AGW (anthropomorphically induced Global Warming) exists”, specifically when it’s needed, although I’ll often use the shortcut ‘GW Deniers’ to mean the same.
Nothing’s perfect, it’s all statistics (sorry Einstein), but it’s good enough to have come a long way.