I see two obvious possibilities: (a) they got embarrassingly few submissions; (b) they got loadsasubmissions form the kind of idiots who believe there is no greenhouse effect. We do know they got at least one submission, because Moyhu published one, and indeed invited comments to improve it; and I did1.
And what about the bozos who agreed to serve on this one-ring circus? Petr Chylek, Richard McNider, Roman Mureika, meh. Terence Kealey, dunno, his bio is weird, in that it says “was Vice-Chancellor [of the University of Buckingham]” but then… what? He’s retired? Gone dolally? Its not clear. RP Sr? You’d have thought he’d have more sense of his own worth. William van Wijngaarden? There’s a talk abstract which is carefully non-commital about everything but irrelevancies. wvanwijngaarden.info.yorku.ca/research-projects/climatechangestudies/ is thin; too thin to justify the GWPF’s “he has published a substantial body of work in climatology”. But no-one expects truth from the GWPF so I shouldn’t complain too much.
In the spirit of inquiry I sent a nice email to firstname.lastname@example.org:
Hi. I notice that you’re chair of this inquiry. You invited submissions – deadline 30th June – and promised to publish all submissions. Can you tell me
1. how many submissions you received
2. when you expect to publish them.
I then realised that the present-day “contact” page prefers email@example.com, so I sent it to that, too.
Update: I received a meaningless answer, pointing me at http://www.tempdatareview.org/news/2015/9/29/international-temperature-data-panel-status-update. Since that didn’t tell me what I’d asked, viz how many submissions they’d got, I asked again.
1. After writing this, I poked around for submissions. Apart from Moyhu, I found one via judithcurry.com/2015/05/02/week-in-review-science-edition-3/ from Ron Clutz. And that was it.