Cancel the Paris Climate Summit

At the end of November, representatives from the nations that signed the U.N.’s 1992 climate treaty will meet — for the 21st time — to implement the treaty’s stated goal of “prevent[ing] dangerous anthropogenic interference with the climate system.”

There’s no need to meet. Nature and capitalism have already conspired to accomplish this.

Since the treaty was signed and adopted, U.N. climate czars have determined that a greenhouse-gas-induced warming of 2.0 degrees Celsius (3.6 degrees Fahrenheit) is the threshold at which climate change becomes dangerous. They also ruled that we’ve already raised the temperature 0.6 degrees Celsius since the mid-19th century.

That’s highly debatable, but let’s stipulate it. We can therefore accrue only 1.4 degrees Celsius more warming before we cross that threshold.

The U.N. estimates various amounts of total warming for what they call Representative Concentration Pathways of greenhouse gases, based upon what they used to call “storylines for economic development.” The highest pathway assumes that humanity will basically continue the same fuel mix of today through exponential economic growth. If the world were on that path, the U.N. says, total warming by 2100 would be about 4.5 degrees Celsius, far into their putative danger zone. A whopping 3.9 degrees Celsius of that will be in the remainder of this century, because of the 0.6 degrees Celsius we’ve already experienced.

(2100 is a nice but arbitrary endpoint. Energy-wise, no one has a clue what the world will look like then, so it’s useless to speculate beyond.)

The decades-long climate kerfuffle is over.

But we clearly won’t be on this pathway. Cheap natural gas is ubiquitous in worldwide shale formations, and where markets have been allowed to act — darn those capitalists — it is rapidly displacing coal for electrical generation, the world’s biggest source of carbon dioxide emissions. It produces roughly half as much carbon dioxide per watt of electricity generated as coal.

That means we’re probably close to the U.N.’s next pathway, which entails a total of 2.8 degrees Celsius, or 2.2 degrees Celsius between now and 2100. But even this estimate is unrealistic.

All of the U.N.’s calculations are based upon an assumption about how sensitive surface temperatures are to atmospheric carbon dioxide — specifically, an estimate that doubling CO2 levels would increase surface temperatures by 3.2 degrees Celsius, which is almost certainly far too high. The U.N. itself admits that the true value could be anywhere from 1.5 to 4.5 degrees Celsius, and in the last five years, 20 separate experiments have been published in the scientific literature detailing an average sensitivity of 2.0 degrees. This is toward the low end of the U.N.’s range and almost 40 percent below 3.2 degrees, the number the calculations are based upon.

There’s very good reason to believe 2.0 degrees is closer to the truth, as atmospheric temperatures, measured both by satellites and weather balloons, show no significant warming in the last 21 years. When this year’s temperatures are finally in (which will no doubt be reported before the end of the year as fuel for the Paris hype), surface temperatures are likely to show a marginally significant warming in the past two decades, thanks in large part to the currently raging El Niño.

Consequently, the U.N.’s estimate of 2.2 degrees of warming between in this century has to get knocked down by a bit less than 40 percent. Add the resultant warming of 1.4 degrees Celsius to the 0.6 degrees Celsius the U.N. says has already happened, and the total warming to 2100 works out to a cool 2.0 degrees Celsius, or precisely the goal of the 1992 treaty.

Nature, by refusing to warm in the fashion assumed in the U.N.’s calculations, and capitalism, in the form of free markets selling shale-derived natural gas, have already done for us what the U.N. says we must do.

The decades-long climate kerfuffle is therefore over. The U.N. should cancel its Paris meeting.

Patrick J. Michaels is director of Cato’s Center for the Study of Science, which is hosting its Preparing for Paris Conference on October 30.