Future generations may look back on climate change as a fortunate sorrow if it proves to have been an early wakeup call for the need to find shared ethics for an interconnected world. Shared ethics are not the same as universal ethics -- the idea we will all agree on all our values -- which are not feasible. But finding some basic human values we can agree on, instead of always focusing on our disagreements, is important well beyond climate change. Among the reasons climate change might function this way is, first, that it affects all of us, making us all personally identify with the harms and risks. Personal identification with a threat is a powerful trigger for ethical concern. Second, the dangers of climate change are universal -- they cross social, cultural, and religious barriers and the North/South divide. So, as individuals and societies, everyone must respond to the ethical issues those dangers raise. That openly challenges the intense individualism that has become dominant in contemporary liberal Western democracies.

Finding some basic human values we can agree on, instead of always focusing on our disagreements, is important well beyond climate change.

Social scientists distinguish between pro-individual and pro-social behaviour. The latter stems from concern for others and a feeling of moral obligation to do the right thing by them, a feeling that research shows is more common than often assumed or recognised, especially by politicians. In a recent article, politics professor Andrew Dobson pointed out that for climate-change solutions to be effective, they must encourage, and certainly not undermine, that moral sense. So not only might climate change provide an opportunity to develop shared ethics, but developing those ethics may help us to find solutions to climate change. Third, climate change problems are not just theoretical and abstract; they are practical and concrete -- another powerful trigger for ethical concern. It's much easier to ignore or dismiss ethical issues raised by situations we don't physically experience. Fourth, we can start from an agreement that climate change is alarming, rather than starting from disagreement, as is more common in ethical analysis. Starting from agreement makes it much more likely we will identify the values we hold in common -- something we routinely fail to do -- and, as a result, reinforce and promote those values. Fifth, responses to climate change will need to be based in earned trust, not blind trust. Earned trust ("Trust me because I will act in your best interests") is an egalitarian concept that requires sharing of information and decision-making. Blind trust ("Trust me because I know what is best for you") is a paternalistic concept that depends on authority, status and power. Using earned trust to address the ethical challenges of climate change will promote such trust in general, and augment social trust on a global scale. Sixth, dealing with climate change provides an important example of science in the service of ethics. It makes us aware that science can help us to find solutions to ethical problems, not just create new problems. Still, a pure technological fix will not be sufficient. We must freely choose to change our behaviour to favour more the common good -- including of future generations. Ethics can help us make that choice and change. Seventh, climate change is a powerful reminder of our obligation to hold our world, nature and the natural (including our humanness) in trust for future generations. The new technoscience, with the unprecedented powers it gives us to change all life, means we must do that in ways no previous generations have had to contemplate. We must reconnect with nature and be guided by ethics that respect nature and the natural, and constantly ask ourselves: What do we owe our great-great-grandchildren? What are our obligations to far distant generations? Can the future trust us? Eighth, climate change is a particularly appropriate context in which to develop a concept of "anticipated consent" as a guide in decision-making. That requires us to ask: Can we reasonably anticipate that future generations would consent to what we both do and don't do now? If not, ethics demand that we change our behaviour. A concept of "anticipated consent" will be ethically valuable far beyond dealing with climate change. In many respects, climate change presents us with a unique opportunity to see whether we can put our ethics into practice on a global scale. Reducing its harms could become a common ethical cause we can all buy into and, in doing so, allow us to bridge all our divisions. Most of all, I propose that dealing with it ethically requires acting with profound respect for all life and what sustains it. And that requires having an acute sense of the finitude and fragility of the Earth, wise ethical restraint and the courage to say "no" -- especially to ourselves -- when ethically necessary. Whether we can do that will be an important trial of whether we can do the same when it's required in relation to many future ethical issues that we are likely to face. Margaret Somerville is founding director of the Centre for Medicine, Ethics and Law at McGill University in Montreal. Her latest book is The Ethical Imagination: Journeys of the Human Spirit.