What I said was:

> Eh, no. I don't trust him because he's written anti-climate change before and doesn't give any sources for his claim that the data is basically fraudulent.

He's clearly a sceptic and that's his right. But I'll give you several points to consider:

a) The author has written a book (several even) where he disagrees with the international consensus about climate change. I'd wager a bet that they aren't all about how the data is missing. So either he's out looking for ways to disprove the theories (which is good) and finding a lot or he's just searching for stuff to hit people with, instead of trying to do serious science. I'm inclined to believe the latter, since the former would mean that a few hundred climatologists from around the world are blatantly ignoring clear evidence and the latter would only mean someone with political motives (or being stupid, corrupt or something like it, or any combination of said things).

b) He has written extensively about how climate change isn't true, but is only now trying to review the data of people that have found climate change to be happening. That's odd.

c) Yes, it makes a difference if he has written anti-climate change before. If he had written pro-climate change before and is now coming to the conclusion that the data can't be checked, his claims are a lot easier to believe because political motives can be ruled out.

It's the same when a climate change sceptic would review the data and find that it supports the conclusions. That would mean that it convinced a sceptic. That's a higher bar to pass than convincing a tree-hugger.

d) The title of the mentioned book is "Climate of Extremes: Global Warming Science They Don't Want You to Know". "They don't want you to know"? He's apparently implying that there's a conspiracy to make people believe climate change exists. That does not give me a whole lot of confidence in his intellect or intentions.

All that makes me distrust the author. Which is fine, I don't need to trust the author to believe facts he reports, as long as there are sources. But he didn't supply any.

So I'm left with an article written by somebody I cannot trust to be intellectually honest about the climate debate and that doesn't contain sources. The only conclusion I can come to is that I cannot trust the "facts" reported in it.

No, I split the sentence in two and showed one of the two parts is wrong. You should have left it out.

You essentially made an ad hominem argument, and I pointed it out.

I do understand the point that when you can not verify the argument, you verify the person.

Which is what you did, but you did it wrong. You compared his beliefs to yours, and since they didn't match you don't trust him.

You can verify the person if you want, but not by comparing his opinions to yours.

Which isn't what I did. At no point have I given my opinion. My opinion has not changed between my two posts, nor has my point. The last post was an elaboration of the first. If you find no issue with the second, then there is none with the first (other than too brief, apparently).

I do not trust the author of an anti-climate change article because he has a pre-existing opinion against climate change AND doesn't cite any sources. If either would have been the opposite, I would have had a different opinion, because then there would be no motive to fudge the truth. Both parts of the statement are important and relevant.