Brian McNair's thoughtful piece deserved a better reception than the ill-informed anti-science nastiness which pervades most of the responses in this blog. The bad, as Yeats said, are full of a passionate intensity ... and impervious to argument or evidence. Raycom, it is actually quite easy to find evidence which supports the theory of human-influenced climate change (if you actually want to.) You could start with the freely-available scientific literature (Nature, Science, JGR, PNAS, Proceedings of the Royal Society etc etc) online or in your local library. Presumably you understand the process of peer review, which is normal practice in all branches of science. The implication of peer review is that published material has been through a minimum of quality control, and is sufficiently robust that the editors can offer it for public comment. This does not mean that it has to conform to the editors' own views - science editors, just like editors in the daily media, like a good argument. (Incidentally, what is difficult is finding sound evidence which refutes the theory of human-influenced climate change, in amongst all the noise.)

Nicco, it is up to the believers of the AGW hypothesis to table the scientific evidence that anthropogenic CO2 emissions have caused measurable global warming. After some 20 years of searching and over US$100 billion of research expenditure, your quoted scientific literature sources have failed to come up with such scientific evidence. The best they can do is assert. Assertion is not science.

In the unlikely event that you are aware of a scientific paper that contains that evidence, then please quote its reference

nicco,

Raycom obviously knows very little about the scientific process, peer review or weight of evidence.

If he did, he wouldn't make such blatant stupid assertions himself.

All he can do is repeat the same old anti-science guff we've come to expect from his ilk.

Best leave people like that wallow in their own mud.

Nicco,

I appreciate your point. I do value science, and I agree that there is evidence of AGW. But you're arguing like a lawyer for the AGW proposition, glossing weaknesses your position, patronising critics. It leaves you vulnerable.

No offence, but mentioning 'Nature' as your first stop for AGW 'facts' is ... careless. Like most science journals, ‘Nature's’ policy is to require disclosure of data supporting the author's case as a precondition of publication. That policy has been widely flouted for pro-AGW articles; in some cases, even the calculations have been withheld. It's PROFOUNDLY unscientific to publish a conclusion without putting both data and calculations into the public domain. In my mind, any publication that does so fails to meet minimum standards for science. ‘Nature’ is a serial offender here, and has also been less than impartial in their commentary. ‘Nature’ and ‘Science’ are not where assertions about AGW are tested. PNAS and JGR are better.

You also bring up peer review. Bad strategy — it works for your opponents. You MUST be aware of the long-standing controversy about 'Pal' review in climate science. Had statisticians been allowed to critique Michael Mann's 'Hockey Stick' paper (they clamoured loudly enough throughout the many years the IPCC highlighted it), that paper would never have been published. The data was cherry-picked, the calculations were simply invalid, the conclusions could not be replicated. ‘Pal’ review was at the heart of ‘climategate’.

True, no science ‘refutes’ the AGW hypothesis. In science, hypotheses are NEVER refuted or confirmed — they’re tested. Competing hypotheses exist in every scientific field, and testing them defines the scientific method. The AGW hypothesis is acceptable to the degree that it can withstand the challenge of counter-interpretations. Unlike mathematics, science NEVER goes beyond CONDITIONAL acceptance of ANY hypothesis. It’s not difficult to find such challenges in PNAS or JGR, though you don’t find many in Nature, Science, or IPCC publications.

It’s not anti-science to challenge AGW tenets. Frivolous challenges actually strengthen your case. They’re not all frivolous, though, and like it or not, science requires you to address them.

Donkeygod

In hindsight it’s easy to ‘attack’ Mann for his TER ‘hockey stick’. I hope you’re not inferring that all ‘hockey sticks’ in AR4 were tainted with the same brush given they were based on completely different data sets than Mann’s original. All 14 show similar trends.

Besides, when corrections were applied, they didn't have world wide shattering significance - you must know that.

Of course it’s not anti-science to challenge AGW tenets; real sceptics do it all the time – and they are addressed in peer review, whether you agree with it or not.

Frivolous and anti-science challenges are made mostly in forums such as this – you must be aware of that.

Further, as to "challenges" in general science journals - I agree. But as you rightly point out, (more nuanced) challenges are covered reasonably well in the more nuanced Journals.

As far as the IPCC "publications", there are numerous references to contrarian publications.