"The revelations of the NSA whistleblower, Edward Snowden, are an ongoing embarrassment for the US government.
Wind your mind back to December 2009, when world leaders converged on Copenhagen to cook up a global climate deal that would solve the problem of rising temperatures.
But it appears the US already knew what everyone else was thinking.
According to documents released to a Danish newspaper by Snowden, the NSA was ready, willing and able to provide "unique, timely and valuable" insights into the negotiating positions of the countries that attended the blockbuster summit.
By monitoring "signals intelligence", the spies would keep US negotiators "as well informed as possible" about "sidebar discussions", informal huddles and corridor conversations during the two week conference.
In other words, the sneaky buggers (well, they do install bugs, don't they?) were giving the US a major advantage in the negotiations.
"It is interesting to have your fears confirmed," says Kit Vaughan from climate campaigners Care International.
He was among those who attended the meeting, known as Cop 15, in the Danish capital.
"All of us thought that this was happening. To know that it was happening is even more worrying."
The Danish Security and Intelligence Service were supposedly in charge of making sure there was no obvious eavesdropping going on.
Known by the acronym PET, many climate campaigners believe these great Danes were, in reality, the lap dogs of the Americans.
"Greenpeace carried out an action. Forty minutes later we were in the pub, celebrating with a few of them. A few minutes later, the police arrested the guys out of the pub," says Mr Vaughan.
"The only way to follow them was to follow the phones and the email traffic coming from that group. It was all monitored."
I put this claim to a Danish source who was closely connected to the negotiations.
"Copenhagen is pretty small: if you suddenly have 15 activists celebrating in a bar, it's not going to be a secret for a very long time," he said.
"You don't need electronic surveillance for this!"
Coming in from the cold
The Danes didn't lend a hand to the Americans in their secret squirrel activities, he says.
In fact, he says, the Danes were a bit naive in this regard.
"We got some Chinese viruses on our computers which we thought was rather odd, but we didn't do that much about it," says the source.
"We didn't use encrypted emails which we probably should have done, but that was five years ago and no one knew about the NSA."
Not only were the US at it, and it would appear the Chinese, but the non-governmental organisations weren't going to be left out in cold either, says Kit Vaughan.
"There are people in the NGO and civil society movement who are very closely aligned with parts of intelligence groups of other agencies. That's the business and the game of climate, there's too much at stake for them not to be."
One element that really soured the atmosphere in Copenhagen was the so-called Danish draft: not one of the excellent local beers, but the text of a deal, drawn up by the home government in an effort to move the talks forward.
Many campaigners believe the US got hold of the document via email intercepts. My Danish source denies this. He points to the fact that wire agencies had a copy of the text two weeks before the conference began.
"All the spying in the world wouldn't have secured an agreement in Copenhagen," he says.
"We all knew the Gordian knot was that China wouldn't accept an agreement that omitted the Kyoto Protocol and the US wouldn't accept one that included it."
"This was impossible to cut through and everyone knew this beforehand."
And so it was that "Hopenhagen" rapidly became "Brokenhagen".
But despite the spies and the failure of the meeting, there's a quantum of solace for those who believe that a global, legally binding treaty is the only way to tackle climate change.
A deal, of one type or another, at Paris in 2015 remains on track.
Somehow, some way, the "zombie talks process" staggers forward."