Over the course of the next year, the Intergovernmental Panel on Climate Change will release the various parts of its Fifth Assessment Report, summarizing what scientists have learned about climate change in the years since the last report was released in 2007.

It’s a massive set of documents — four sections, hundreds of pages long, thousands of citations. Ironically, for all that, it’s not likely to tell us much that we didn’t already know. Climate change is happening, the IPCC will say, and more than half of the change is attributable to humans. The panel told us roughly the same thing six years ago … and six years before that. It’s safe to say, at this point, that the evidence points firmly toward the reality and risk of global warming.

So why hasn’t there been much political change?

For those of us who long ago accepted the evidence for climate change, the default assumption tends to go something like this: Too many politicians are anti-science and have no interest in making the decisions that scientists say need to be made. While there’s certainly truth to that, there are a couple of other questions that we don’t ask ourselves often enough. First, what is the science actually telling us? Second, what should truly objective evidence-based political decision-making look like, anyway? If your answers to those questions just happen to match up identically with your own political ideologies, technological preferences and ideal lifestyle, then I have a modest proposal for you — you’re doing it wrong.

Not That Kind of Doctor

In 2006, climate scientist Gerald North sat before a congressional committee to deliver the findings of a National Academy of Sciences report on surface temperature reconstructions for the last 2,000 years. There was nothing truly surprising in that report — the evidence pointed toward man-made climate change. But North’s former colleague Ian Kraucunas said there was one big memorable moment during the testimony. “One of the committee members asked what do you think this means, in terms of should we put a tax on carbon,” Kraucunas says. “And Jerry North, in this Texas drawl, says, ‘I’m not that kind of doctor.’”

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.

Climate scientists exist on a spectrum. Some, as North did in that hearing, will tell you their job is to simply deliver the facts about what the climate is doing. Science is their area of expertise, not policy. Other climate scientists vehemently disagree with that approach, and a lot more will fall somewhere in between. But, regardless of what an individual climate scientist thinks he or she should be doing professionally, there really are some things climate science data tells us and some things it doesn’t.

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.

Clash of Values

There’s not much room for legitimate disagreement about the reality of climate change. But there’s a lot of space for reasonable people to come to completely different conclusions about all the stuff climate science doesn’t tell us. That’s because those decisions aren’t just based on data — and, in fact, they shouldn’t be. Instead, they’re about the intertwining of data and personal values. And that’s where things get messy.

Gavin Schmidt, a climate modeler with the NASA Goddard Institute for Space Studies, suspects that the bulk of the disagreements Americans have over climate change have less to do with science than with the inevitable clash of different values (or, more frustratingly, with often-erroneous assumptions we make about other people’s values). It’s impossible to make policy without values, he says. And that doesn’t mean mixing rational science with irrational beliefs. Values aren’t really rational or irrational, Schmidt says. They’re just part of who we are and how we make decisions — and you’re never going to sidestep that.

Why do we spend so much time debating science? The science is solid. It’s the values debate that shapes what the policy should actually be.

Kraucunas agrees. It’s easy to understand if you think about a political decision that’s less contentious. Say you have $10 million, and you have to choose whether it goes to one of two programs. Do you spend that 10 large on mosquito nets in Africa, or do you spend it on cancer research in the United States? For most of us, the answer wouldn’t really be about evidence; it would be about what we value the most and why.

So, given that, here’s a question: Why do we spend so much time debating science? The science is solid, and its conclusions haven’t changed appreciably in more than a decade. It’s the values debate that shapes what the policy should actually be. It’s the values debate that we don’t have a good grasp on. Even within groups of people who supposedly agree on what we should do about climate change, our values — and our solutions — can be wildly different.

“Take Naomi Klein, for instance,” Schmidt says. “Sometimes she makes a good point, but I don’t share her values. So when she starts talking about climate change as a rod to break capitalism’s back, she loses me. She clearly has a political agenda that’s different from mine. But if we both say, ‘We should do something about climate change,’ there are people who will think we totally agree on what and why.”

Real people aren’t culture war caricatures. And polls have shown for years that Americans want to make changes to the way we make and use energy.

That misperception is a problem because it creates a political climate where science becomes a proxy for the largely unspoken values debate. People who actually agree assume they disagree. People who disagree assume they agree. And everybody thinks they know what’s motivating everybody else. Worse, it sets up a situation where it’s easy for individuals and groups to mesh the science and their values in such a way that everybody ends up deciding the science supports their values — and only their values. Anybody who denies something held true by another must, clearly, be denying science.

Make the Silent Loud

Schmidt has a solution: Make the silent loud.

It’s time to start talking about our values. It’s time to be explicit about what we believe and why, and how our beliefs affect what we think should be done with the science of climate change. We’d then be able to shift the debate from the science (which, again, isn’t terribly debatable) to what we’re all really talking about, anyway. We’d then be able to start working past the fake divisions that often make us think we have less in common than we do. Real people aren’t culture war caricatures. And polls have shown for years that Americans want to make changes to the way we make and use energy. Even if we don’t always agree on what those changes should be or why they should be made, that’s a better place to start a discussion.

Nobody expects this approach to, as Schmidt puts it, lead us all hand-in-hand into Kumbaya land. There are some real fundamental disagreements happening here — particularly about the role of government — that aren’t just going to magically go away. But actually talking about the places where a majority of people might be able to find common ground is more likely to finally get us some real political change than simply waving the banner of science and making assumptions about each other. View Ensia homepage