This discusses the source of that 97-98% consensus claim.
In brief, 10,257 surveys were sent out.
The surveying outfit received 3,146 replies to the survey request.
Of the respondents, 77 were judged to be climate scientists deserving of a valid opinion.
And of those 77, 75 agreed (97.4%) with two questions that have been sold as saying mankind is responsible for global warming.
The two questions were, one:
“When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?”
Good grief. I'd absolutely answer "yes" to that one. The end of the Little Ice Age is generally given as 1850 (and the temperature nadir of the Little Ice Age would have been many decades before that endpoint), so I'd be shocked if the planet didn't warm from that time period even if no human life existed on the planet.
The second question:
“Do you think human activity is a significant contributing factor in changing mean global temperatures?”
If by "human activity" you mean things like agriculture and deforestation in addition to sending carbon dioxide into the air from industry, I'd probably say "yes," humans have affected climate.
Maybe even "significantly." But I could never say that humankind's use of fossil fuels is the dominant factor. I take it that this factor is judged by climate scientists to be significant only since 1950. So already we have a century of overall temperature rise that you can't blame on evil oil and coal.
I'll add that you can be a "denier" and believe that it would be good to gradually replace coal use (especially) for energy generation with less polluting energy sources--but don't wreck economies to do it before replacements are ready and affordable.
Say, we could frack natural gas for a much lower carbon footprint than coal, now couldn't we?
Oh. Sorry for mentioning an inconvenient truth.
Yet since 1950, we can point to a period to the late 1970s that witnessed temperature declines (blamed on mankind and said to indicate a new ice age) and since the late 1990s, flat global temperatures until today. So since 1950 we've had but two decades of rising global temperatures to justify claims that mankind is warming the Earth dangerously. Oh, and the climate models, of course. Which are not data. And which don't account for past temperatures very well, so why do we accept their predictions of the future?
But depending on my mood, I could easily have answered "yes" to the second question. Yet I can understand why even 2 climate scientists would not answer yes to both questions.
I guess what makes me a real "denier" is that I see no reason to panic and inflict economic and personal freedom losses on all of us to allow our Warminista elites to guide us to a carbon-free future.
The problem with this survey and how it is portrayed is the same as climate science in general: reasonable questions are being inflated into Chicken Little-levels of hysteria that justify drastic, expensive actions by reasonably enlightened despots to save us from ourselves.
I deny that is a sane response.