In a discussion of climate change and its potential solutions, it's important to consider what we're saving, and what we're saving it for. If the goal were only biological survival in the narrowest sense, the problem of climate change would be greatly simplified. For example, imagine a group of geneticists willing and able to reengineer humans so that they no longer posed any threat to each other or their environment. I'm not advocating this, nor is it even my idea: It's the central premise of Margaret Atwood's dystopian novel "Oryx and Crake." The geneticists' motto could easily be something like "Preservation of [our] species has to be the primary value."
Most people would (or should) be horrified by the world "Oryx and Crake" and its sequel describe. The books indirectly draw attention to the fact that climate change threatens much more than mere biological survival. What's at stake is the survival of human values. Increasingly those values are no longer tribal or national but global, at least in theory. Science has flourished in the age of reason, but that age was a long time coming, and its persistence is by no means assured, even in the short term. Science is inextricably entwined with civilization and democracy, and all the rights and responsibilities they entail. The ethical assertions of equality and universality at the core of the American and French revolutions sustain science just as much as the humanities. Science sinks or swims with civil society. In Margaret Atwood's nightmare, science is doomed.
By mitigating climate change, we're trying to save not merely people's DNA, but their culture, which paradoxically is also the source of climate change. We're trying to save not just literacy, tolerance, and reasoned debate, but also art, music, and all the less obvious cultural artifacts that make life worth living. This is what makes the problem of climate change so intractable. It's not enough to just reduce CO2. The challenge is to reduce CO2 humanely, preserving not only the oceans and forests but also the fragile traditions of increasing civil rights and intellectual freedom within which science and so much else have evolved. We're more likely to succeed if we're clear about the goal.