What did the UN climate change talks in Copenhagen achieve? Our governments failed to agree a deal which might have avoided a global catastrophe. They did nothing but take yet another "important first step". We've had nearly two decades of those.

It's likely that Copenhagen is a long-term disaster for the planet and its people, but it might have another, more immediate consequence for you right now. Your moral obligations might have just changed dramatically. In situations like the one we're in now, the demand for action shifts from our leaders to us. They missed what might have been our last chance to take to take concerted, worldwide action on climate change, so the rest of us have to do something about it. Their failure means that we're all eco-warriors now.

When things go smoothly, you do your civic duty by casting a vote, paying your taxes, and generally keeping out of trouble. It's enough to leave it to the ones in power to think things through and make certain choices for you. In rare circumstances, though, our obligations enlarge, and it's up to us to do the right thing when no one else will.

When the state perpetuates injustice and human suffering, when there's real urgency, when other avenues of protest have done no good at all, your civic duty becomes something very substantial. You have to bring change into the world, and a vote is not enough. Anything less ties you to an ongoing wrong. Civil disobedience and other direct efforts to bring about change are the only options you have.

It's no longer any good just hoping that the men in suits will come up with a decent solution. They messed it up. It's not enough to click a link and send a message to your representative or even go on a march. None of it is enough when the people you petition fail again and again to do the right thing. Perhaps it's now up to us to make trouble for them, to leave our governments no choice but to act, to get in the way, make business as usual impossible, and force real action against climate change. Think of all the usual examples, large and small, of human beings at their finest: the end of slavery in America, the civil rights movement, suffrage, India, the velvet revolution, the poll tax protests and on and on. When human beings see that something is wrong we almost always change for the better. Sometimes we need our noses rubbed in it, but we do the right thing in the end. The developed and developing worlds are doing something wrong – we're all causing suffering to people alive right now and to great numbers of those who will come after us. If civil disobedience was warranted to stop past injustices, isn't it warranted right now to stop what is probably the greatest amount of harm any group of human beings ever inflicted on any other?

The green movement has always suffered from the lack of a clear target. How do you protest against something that's all around us, a fossil-fuel burning world we all inhabit and depend upon? Do you chain yourself to yourself and insist on a carbon tax on the things you value most? With the failure at Copenhagen we have for the first time a clearly delineated and easily accessible object for our protests: our governments.

What about the so-called deal-breakers at Copenhagen? It's being said that what really stood in the way of a binding conclusion is China and America failing to see eye to eye. The philosopher Peter Singer argues that sanctions were warranted against South Africa because it harmed its own people. The world's biggest polluters harm not just their own people, but people all over the world. How much greater are sanctions warranted in their case, compared with South Africa?

But maybe this isn't the right way to think, and anyway we've all had enough doom and gloom. It might be wrong not because it's over the top, but because it depends on a conception of politics that no longer fits the world as it is now. Perhaps global treaties and talks and sanctions are not part of the solution to climate change. Those are the bones of something that died near the start of this awful millennium.

Maybe the solution never was a deal at Copenhagen – who really thinks that climate change has just one big answer? What we need are a billion different solutions, perhaps billions of little revolutions in thinking and acting all over the world. The good news is that such things do not depend on a handful of negotiators sitting around a table. What matters are people like you and me who see the world for what it is and do something about it. There's room for a little hope still, the hope that even though our leaders fail to do the right thing, the rest of us will either push them into action or get on with it without them.

James Garvey is secretary of the Royal Institute of Philosophy and author of The Ethics of Climate Change