Traditionally, there’s a piece of graffiti underneath the toilet paper dispensers at Australian universities: “Arts degrees. Please take one.”

At first glance, the poster for Earth Hour seems equally cynical: “Your light switch is your vote,” it reads.

It’s a Situationalist critique of parliamentarianism, a May 68-style indictment of the two party system (on, off; on, off), a bitter denunciation of …

Oh, wait. It’s nothing of the sort.

Earth Hour began two years ago in Sydney, the brainchild of Fairfax newspapers, the World Wildlife Fund and the Leo Burnett advertising agency. Since then, it’s spread across the planet. Tomorrow night at 8.30 pm, the organizers expect an astonishing billion people to turn out their lights for an hour.

As to how much carbon this will save, the short answer is … it’s complicated. As it turns out, the paraffin candles to which most people resort are actually very greenhouse gas intensive.

Of course, the real point lies in the symbolism, as the Earth Hour FAQ explains:

Flipping the switch for Earth Hour is a way for people to get involved and demand action wherever they are. It’s easy so everyone can participate no matter their location, age or income level. Switching off your lights is a symbol of your support for effective action on climate change, which is represented in our Vote Earth campaign. Flicking the switch is a vote against climate change.

But hang on. When it comes to voting against climate change, wasn’t that what many of us did back in November 2007? And what happened? Late last year, Kevin Rudd and Penny Wong delivered their proposal for carbon cuts. At the time Ben Eltham wrote in New Matilda, “I hate to be apocalyptic and all that, but it’s hard to be optimistic about the future of our country when our Government — which claims to be taking climate change seriously — has just committed to letting it run its course. […]A 5 per cent target means disastrous levels of global warming. It’s as simple as that.”

So if Rudd ignores our actual, ballot box votes, will he really be swayed by our symbolic, light-switch ones? Organisers say that they want to pressure the world’s leaders as they attend the Copenhagen climate conference. Yet the PM, the Deputy PM, the Minister for the Environment and just about every other Australian politician have all publicly urged us to take part in Earth Hour, with a bipartisan enthusiasm scarcely suggestive that they fear being forced to do anything they don’t want. On the contrary, it seems more likely that they’ve identified Earth Hour as a handy way to accumulate environmental cred without any pain whatsoever; a project less putting demands on our leaders and more about our leaders putting demands on us.

Furthermore, the Saturday night time slot means that Earth Hour avoids targeting the worst polluters, since most corporations do their dirty work doing business hours.

But, as the kids say, that’s not a bug – it’s a feature. Earth Hour is deliberately business-friendly, so much so that the sponsors of the Australian franchise include BP, the oil company that’s one of the world’s largest single corporate emitters.

Yes, cynicism is cheap, and maybe this kind of protest-lite serves to raise awareness more generally. If so, where’s the harm?

In their book Climate Code Red, David Spratt and Philip Sutton argue that the situation has long since passed the time when business-as-usual solutions can be credible.

Spratt puts it like this:

[S]olving the climate crisis cannot be treated like a wage deal. It is not possible to negotiate with the laws of physics and chemistry, and believing that it [is] reflects only an ignorance of the task at hand. The planet cannot be traded off. There are absolute limits that should not be crossed, and doing something, but not enough, will still lead to disaster. This the Government appears not to understand at all.

The problem, then, with purely symbolic actions like Earth Hour is that they might actually foster cynicism more than dispel it. Spratt, for instance, argues that only a mobilization on the scale we saw during the Second World War will make any difference. If that’s right, then reassuring people that all they need to is turn off a switch is deeply disorienting.

There’s another slogan from the 68ers appropriate for eras in which conventional pragmatism no longer cuts it. To be realistic, you need to demand the impossible.