The data does tell us that climate change is happening. It does tell us that this change is linked to human behavior. It does tell us something about how certain levels of atmospheric greenhouse gases will impact our lives. And it does give us guidelines about how much we should reduce greenhouse gas emissions, and by when, in order to avoid negative consequences. What climate science doesn’t do is tell us how to value the different policies to reduce emissions, or how to deal with unintended consequences of those policies so we get the most benefits for the least harm.
http://ensia.com/voices/the-value-of-talking-about-values/