In Science this week, a commentary (subscription required) from John Sterman, who studies systems thinking at MIT’s Sloan School of Management, argues that the public may shy off of action against climate change because their basic mental model of the problem is wrong. People don’t intuitively understand how changing rates of carbon dioxide emissions affect the overall concentration of the gas in the atmosphere, Sterman says. In fact, they often make mistakes when thinking about how ‘inputs’ and ‘outputs’ sum up to form a total ‘stock’ – “even in simple, familiar contexts such as bank accounts and bathtubs”.

Time’s Bryan Walsh covers the piece today, tutting over the “tremendous gap” between knowledgeable scientists who favour aggressive steps and confused laypeople who don’t. Walsh wants experts to “better explain in clear English the dynamics of the climate system, and how to affect it”. Matt Nisbet at Framing Science goes a little further: “What’s needed is not simply getting more scientific information out there, but rather new methods for communicating about the problem that are adapted to the background of targeted publics, journalists, and decision-makers.”

But I’m not convinced that the apparent crisis of understanding Sterman points to is really a crucial barrier. Here’s the background: research Sterman published last year with co-author Linda Booth Sweeney of Harvard found that even MIT grad students make rudimentary mistakes when asked how to stabilize atmospheric carbon dioxide concentrations. Nisbet sums up:

In the experiment, MIT students with advanced training in either the sciences or economics were asked to read descriptions from the IPCC summary for policymakers that depicted the long term accumulation of CO2 in the atmosphere. When asked then to sketch what they estimated to be the emissions path needed to stabilize atmospheric CO2, nearly 2/3 of the elite MIT students erroneously reasoned that greenhouse gas emissions can stabilize even though emissions would continue to exceed the rate of removal from the atmosphere.

The students typically thought that stabilizing carbon dioxide emissions at current levels would likewise stabilize carbon dioxide concentrations at current levels. The right answer is that emissions need to be cut drastically – by over 50%, given the numbers in Sterman’s example. This is an instance of the more general problem where “people have difficulty relating the flows into and out of a stock to the level of the stock”, says Sterman.

Sterman takes something of a logical leap, though, in connecting this mistake with poll results showing that majorities in the US, Russia, China and India – all important emitters – favor a ‘wait and see’ or ‘go slow’ approach to lowering emissions. (More on recent climate poll results in this post, by the way.) He writes:

For most people, uncertainty about the risks of climate change means costly actions to reduce emissions should be deferred.

But that’s an answer to the question of when to take major measures against the risks foreseen by climate experts. It’s not about what those measures would look like, in terms of emissions trajectories.

It can’t help that greenhouse gas stocks and flows mystify the average MIT student, even after the IPCC tries to explain them. But that problem is separate from the difficulty of getting support for an immediate, rapid response to changes that scientists expect to unfold over the long term.

As Sterman himself notes, “‘wait-and-see’ works well in simple systems with short lags.” The Earth’s climate is not a simple system with short lags. Sterman then downplays that unrealistic view in comparison to the stock-flow misconception. But if the polls are flagging up one climate science message that hasn’t come across, it’s this: on a complex planet rife with both physical and bureaucratic inertia, decisions made today take decades to have a meaningful effect.

Anna Barnett