Live Earth:Among a number of things that did not happen yesterday in the wake of Live Earth, the world's carbon dioxide emissions did not plummet to zero, and international air travel did not immediately cease. Rock stars did not rise as one to trade their private jets for bicycles.
And yet - as the shock that the planet had not been saved in a day began to fade - the scandalous possibility presented itself that Al Gore's seven-continent, 24-hour concert series had been really rather impressive, and might yet prove to have been hugely important.
This was despite, not because of, many of the pronouncements from the Wembley performers, which ranged from the asinine ("we're here to save the Earth, yeah?") to the obvious ("let's all get smaller-ass cars!").
The sellout crowd of 66,000 had clearly come for the music - Metallica, Madonna and the Red Hot Chili Peppers specifically - as opposed to the climate. But if you tell a world audience of up to two billion people, over and over again, that they should use energy-efficient lightbulbs, do their washing at 30 degrees, and never leave their TVs on standby, you can hardly fail to have some kind of effect.
The direct role of Live Earth in stimulating such small changes will never be measurable. But as the atmosphere at Wembley finally started to crackle on Saturday evening, you felt that would have made a poor excuse for not trying.
To observe that the London line-up was deeply middle of the road was to miss the point entirely. The best interpretation of Saturday's concerts was precisely that climate change moved to the middle of the road, fostering a vague but mainstream sense that "something must be done". Significantly, Wembley concertgoers seemed to share the suspicion that Live Earth's message wasn't getting through - except to themselves.
"You do get a pretty strong feeling that nobody's taking any notice of the issue," said Angus McKeown, from Chiswick. "I'd be surprised if 10 per cent of the people here knew what it was all about," added Fiona Black, a New Zealander.
It was acknowledged from the stage that the performers' own carbon footprints did not bear close examination. "We did have to fly some people in on private jets," Ricky Gervais conceded. "They do use up a lot of fuel - but it saves queueing." When Johnny Borrell of Razorlight told the crowd "You can hear us, but we can't hear ourselves!" he might have been talking about the climate-change message, instead of the technical problem that dogged Wembley.
Still, it would have taken steely cynicism not to acknowledge something in the air, however intangible. It was not a politically angry event, and perhaps it should have been - but the call to personal action was unmissable.
"In Africa there's a proverb that says 'if you want to go quickly, go alone. If you want to go far, go together'," Gore said in Washington. "We have to go far, quickly."