Very little other than the bleedin’ obvious I fear. Inel laments her lack of access; but http://blog.petedecarlo.com/ has read it and provides a copy of the Nature comment, but not the Proc Royal Soc original. Not having read the original, I’m not sure what was in it worthy of publication; the lack of a trend in solar is known already. But the septics are rather like Monty Pythons Balck Knight: no matter how many limbs you chop off they hop around on one leg or offer to bite your shins, and they need to be stomped on every now an again.
Even if you’re mad enough to insist that solar forcing changes might be strong enough to explain climate change; or that they are amplified by some mysterious mechanism involving clouds or space aliens; you’re still left with the minor problem that (a) the trend in solar, if there is one, is downwards and (b) any trend is much smaller than the 11-y solar cycle which you certainly don’t see in the sfc data; see wiki for example.
The new paper won’t stop the loonies, of course; nothing will (and anyway, this being published in Proc Royal Soc and nature just means its part of the Vast Global Warming Conspiracy ™). But it may be handy for editing into wikipedia.
[Update: the paper is available (thanks F) and the abstract is There is considerable evidence for solar influence on the Earth's pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth's climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures. -W]