Climate scientists undermine their own science by avoiding the best case scenario

It might not be so bad.
It might not be so bad.
Image: Reuters/Yves Herman
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The conventional wisdom on risk, supported by behavioral economics literature, is that most people can’t understand it. The research finds the human mind does funny things when confronted with uncertainty about the future. People tend to distort probabilities and become either too pessimistic or optimistic, depending on their biases.

Perhaps I cling too strongly to my faith in rationality (my own bias), but I believe most people can make smart decisions when faced with risk—they just need to have it explained to them the right way. Conveying risk is hard but it’s important to do, especially when there is a small, but serious chance of facing danger. That’s why I was dismayed to read that several climate scientists, normally a measured bunch who understand risk and uncertainty better than anyone, are going rogue.

Some are moving off the grid. Others use more forceful language and underplay the uncertainty that still exists. Eric Holthaus writes in Rolling Stone, “Of the two dozen or so scientists I interviewed for this piece, virtually all drifted into apocalyptic language at some point.”

Considering what’s at stake, the extreme measures and playing up the stark predictions are understandable. But exaggerating the likelihood of extreme outcomes not only give deniers ammunition, it undermines convincing—even if not entirely certain—science. Gernot Wagner, the lead senior economist for the Environmental Defense Fund and research association at Harvard Kennedy School, told Quartz: ”Even enviros get it wrong, they have a knee jerk reaction against anyone who questions the science.”

Wagner and Martin L. Weitzman co-authored the recent book Climate Shock: the economic consequences of a hotter planet, and they share my view that people can make good decisions when faced with an uncertain future. They use finance theory to argue the presence of risk is precisely why we need to limit carbon emissions sooner rather than later. In finance, risk poses a cost. You can pay to reduce it and often, the sooner you do, the cheaper it is to deal with the risk.

And the fact is, there still exists considerable uncertainty around the consequences of climate change. We know the planet is getting warmer. According to a report from the Intergovernmental Panel on Climate Change (IPCC), the last 30 years may be the warmest in the last 1,400 years in the Northern hemisphere—the globally averaged temperature increased 0.85°C from 1880 to 2012.

We also know that humans are largely to blame. But our precise share is hard to know. Some of the temperature increase is caused by man and some of it may be naturally occurring because global temperatures naturally vary. The evidence is very compelling that human activity is responsible for a large share of global warming. Since the industrial revolution, humans have burned lots of fossil fuels, which release carbon dioxide into the atmosphere. The fossil fuels have increased the atmospheric concentrations of CO2 to unprecedented levels, at least within the last 800,00o years. We’ve known since the 19th century that higher levels of CO2 increases the earth’s temperature. The fact that we put lots of CO2 into the atmosphere and temperatures have since increased makes a compelling case we’re largely at fault.

We’re already seeing the effects. According to the IPCC:

It is likely that the frequency of heat waves has increased in large parts of Europe, Asia and Australia. It is very likely that human influence has contributed to the observed global scale changes in the frequency and intensity of daily temperature extremes since the mid-20th century. It is likely that human influence has more than doubled the probability of occurrence of heat waves in some locations. There is medium confidence that the observed warming has increased heat-related human mortality and decreased cold-related human mortality in some regions.

But we still don’t really know what it will mean for the planet long-term. Humans are on track to double the amount of CO2 in the atmosphere by the end of the century. But how much that will increase global temperatures and how the planet will respond remain big unknowns. The current projections (the same for the last 30 years) estimate that if CO2 concentrations double, temperatures will increase between 1.5°C and 4.5°C. That’s a huge range. A 4.5°C increase could be catastrophic and more than that could make the planet uninhabitable. Wagner estimates there’s a 10% chance of a catastrophic outcome. “That may be unlikely, but it’s a huge freakin’ problem,” he told Quartz.

On the more positive end of the spectrum, temperatures might not increase much and the effects will be fairly benign—but that’s also a tail case. The most likely outcome is a rise in temperature that will change how we, especially poor people, live and cause more extreme weather. But the range of consequences is rarely communicated, John Richardson writes in Esquire:

Barring unthinkably radical change, we’ll hit 2 degrees in thirty or forty years and that’s been described as a catastrophe—melting ice, rising waters, drought, famine, and massive economic turmoil.

He later explains why some climate scientists feel a need to go so extreme:

As Mann sees it, scientists like Schmidt who choose to focus on the middle of the curve aren’t really being scientific. Worse are pseudo-sympathizers like Bjorn Lomborg who always focus on the gentlest possibilities. Because we’re supposed to hope for the best and prepare for the worst, and a real scientific response would also give serious weight to the dark side of the curve.

As a pension economist I understand the temptation to over-emphasize the worst case. Pension trustees and commentators often exploit the existence of risk to undermine retirement security. Suppose you don’t have enough money to fund pension promises made to future retirees. Odds are that will be a big problem and subject vulnerable people to poverty in their old age. But there’s a chance that if you do nothing things will work out. Your investments may all pay off, people might die younger than you expect, or the economy may grow. It kills me to hear some argue that the slim chance of the best case scenario justifies a wait and see approach, and—worse and more common—continuing to make new promises that can’t be paid.

It’s tempting to shout from the rooftops that this is a disaster waiting to happen, because the downside is so scary—even if it will only impact our grandchildren. More so for climate change where the stakes are so much bigger. But that only gives skeptics room to question climate scientists’ findings. If anything, the existence of uncertainty provides the best case for swift action because the solutions (cap-and-trade, investment in renewables) are relatively cheap compared to what they will be in the future if worst cases are realized.

People can understand this, and be willing to pay now to protect themselves—even if total disaster is unlikely and not imminent. After all the market for insurance exists, but there exists an entire industry that educates people on risk and why they should pay to minimize it.