In September 1945, the classical liberal scholar (and future Nobel laureate) Friedrich Hayek published “The Use of Knowledge in Society.” One of the most influential articles in modern economics, it explained that far-reaching government policies often fail because policy makers invariably lack all the knowledge required to understand a problem well enough to solve it. Consequently, government policies frequently backfire, trigger unintended consequences, or simply prove unavailing.

Examples of Hayek’s insight, often called “the knowledge problem,” abound. Urban renewal tore apart once-vibrant communities, displacing tens of thousands of residents or relocating them into housing projects that became centers of poverty and crime. The war on drugs resulted in mass incarceration, yet drugs remain widely available and overdose deaths are at or near an all-time high. Crop subsidies have routinely led to overproduction, distorted markets, and the enrichment of agribusiness giants at the expense of small farmers. Minimum wage laws, intended to boost the earnings of vulnerable workers, invariably cost many of those very workers their jobs.

Time and again, reality makes hash of the misbegotten assumption that politicians and regulators have sufficient information to plan or fine-tune complex economic systems. The bigger and more complex the system, the more likely that government policies designed to control it will turn out to be ineffective. And what system could be bigger or more complex than planetary climate change?

In a peer-reviewed study published last month in the journal Science, an international team of climate researchers and econometricians analyzed more than 1,500 climate policies enacted in 41 countries between 1998 and 2022. Their conclusion: “We identified 63 successful policy interventions with total emission reductions between 0.6 billion and 1.8 billion metric tons” of carbon dioxide.

In other words, roughly 96 percent of government policies aimed at reducing emissions were largely unsuccessful. And the 4 percent that did have a measurable impact managed to reduce greenhouse gases by a global total of, at most, 1.8 billion metric tons. That amounts to just over two-tenths of 1 percent (0.23 percent) of the 778 billion metric tons of CO2 emitted by those nations in the first two decades of this century. The emissions cuts required to reach the targets specified in the 2015 Paris Agreement — a reduction the United Nations calculates at 23 billion metric tons per year by 2030 — remain far, far out of reach.

The authors of the new paper make a valiant effort to assign their findings a silver lining. The relatively few policies that succeeded in lowering emissions were those that involved “price-based instruments” — which, as one of the researchers explained to The Wall Street Journal, “means carbon pricing, and it could be energy taxes, it could be vehicle taxes.” So the researchers suggest that governments would do best to devise policies that combine pricing with other kinds of control — lower taxes plus stricter regulation, for example, or mandatory minimum carbon prices plus new efficiency standards.

To their credit, though, the authors acknowledge the inherent difficulty of crafting climate rules with any confidence that they will have the desired effect. “Despite more than two decades of experience with thousands of diverse climate policy measures gained around the world,” they write, “there is consensus in neither science nor policy on this question.”

Or, as senior editor Jesse Smith observes in Science’s introduction to the new paper: “It is easy for countries to say they will reduce their emissions of greenhouse gases, but these statements do not mean that the policies they adopt will be effective.” By now there is little doubt that the policies most commonly adopted to address climate change and curb greenhouse emissions — enormous subsidies for green energy and ever-tighter restrictions on the use of fossil fuels — have not been effective.

After a quarter-century of increasingly clamorous alarms about CO2 and the imposition of sweeping laws and regulations to curtail greenhouse gases, governments can report very little accomplishment. “Global fossil fuel consumption and energy emissions hit all-time highs in 2023,” Reuters reported in June. Renewable energy is up a little, thanks to all those subsidies, but its growth has been in addition to conventional fuels, not instead of them.

The moral of the story is that what is true of housing policy or health care policy or agricultural policy is just as true of climate policy. It is very difficult for governments to knowingly and wisely change how society functions. Legislators and regulators rarely possess the necessary information to do so. They may have technical expertise, but they lack the tacit data and intelligence that is dispersed among countless individuals — subjective preferences, local conditions, changing circumstances, unspoken motivations.

In 1945, Hayek knew nothing of a climate crisis. But he did know that the “knowledge problem” never goes away. It is always sensible for policy makers to be modest about their ability to effect change. And the greater the change they envision, the more doubt they should entertain of their ability to achieve it.