My greener friends are rejoicing over the apparent “conversion” of Richard Muller, head of the Berkeley Earth Surface Temperature (BEST) research team, from “climate change skeptic” to believer in global warming. A closer read of his New York Times op-ed, published on July 30, during what is climatologically the hottest week of the year, would certainly cool their enthusiasm.

In it, Muller discusses the fact that the surface temperature of the planet indeed is warmer than it was at the end of the Little Ice Age in the 19th century. While not one climate scientist finds this at all newsworthy, his “admission” has been ballyhooed in environmental circles as a defection that will end the Hot War. Trouble is, Muller’s statements don’t come close to any sort of radical retraction — and there is evidence his conclusions are obviously flawed to begin with.

There are three philosophies in the world of global warming. Loudest are the “hotheads,” who maintain that drastic (and impossible) measures are needed to curtail the emission of greenhouse gases and prevent the seas from rising dozens of feet in a hundred years. The data relied upon by this segment is suspect, but their alarmist message garners more than its share of attention.

The recognized antithesis of hotheads are the “flatliners,” who contend that there is no measurable warming caused by increasing atmospheric carbon dioxide. Their bible is the lack of warming in the last 16-odd years, when CO2 levels have risen the most. They do have a problem explaining the rise in temperatures in the preceding decades.

In the third school, where I find myself, reside the “lukewarmers” — those who argue that carbon dioxide indeed is warming surface temperatures, but that its effect is modest and that we are inadvertently adapting. Our mantra: “It’s not the heat, it’s the sensitivity.” In other words, most climate projections assume that surface temperature is overly sensitive to “forcing” from carbon dioxide. Our bible consists of observed temperature trends as CO2 increased in the last several decades.

I would like to welcome Dr. Muller to the noble fellowship of lukewarmers.

In his op-ed, he forecast that land surface temperatures will rise 1.5°F over the next 50 years. That’s about the same amount that they rose since 1900 — and in the intervening period, life expectancy doubled and per-capita income in constant dollars rose tenfold in the United States.

Muller wrote an important caveat, which is that warming would be much greater if atmospheric carbon dioxide rocketed upwards. Rapidly declining emissions in the U.S., resulting in large part from the exponential substitution of natural gas (sourced from shale), instead of coal for electrical generation, suggest this is not likely. Shale is ubiquitous worldwide, and what began here is likely to spread around the planet.

Note that Dr. Muller is talking about land temperatures, which applies to about 30% of the earth’s surface. Given that the remaining 70% that is water tends to warm at about 60% of the land rate, his global warming forecast is 1.1°F by 2060, which is precisely lukewarm.

For comparative purposes, the median 2010-2060 warming predicted by the United Nations’ Intergovernmental Panel on Climate Change (IPCC) is around 2.7°F. NASA’s James Hansen, the head hothead, has it at around 2.4° for his “Scenario B,” which implies some reduction in emissions from “business-as-usual” (BAU). “Scenario A,” which Hansen explicitly labels BAU, yields a whopping 5.6°, which Hansen now says is on the high side.

So what does the hothead community think of Muller?

For one thing, they can’t be happy with his science, which attributes past warming almost exclusively to carbon dioxide increases. Hansen has a whole host of other “forcings,” including black carbon (soot) that Muller simply eschews.

The hotheads are also surely upset that Muller doesn’t acknowledge that sulfate emissions from the combustion of coal and forests countervail warming.

Penn State climatologist and renowned hothead Michael Mann gave Muller’s conclusions his review in a Facebook post from last weekend: “At this rate, Muller should be caught up to the current state of climate science within a matter of a few years.”

Susan Solomon of the National Oceanic and Atmospheric Administration has to wonder how Muller could have ignored the effect of water vapor changes in the stratosphere, which she says are responsible for 15% of warming since 1980 (and are also implicated in the lack of warming since 1996).

As a result of these and other peccadilloes, the BEST team has yet to publish one peer-reviewed paper, despite conspicuously dominating the op-ed pages for a year now. Their critical paper on the “urban heat island” — which concludes there isn’t one — has been outright rejected. Apparently, the BEST team doesn’t believe that it is warmer in downtown Washington, D.C., than it is in rural Virginia, thanks in part to the waste heat from all the money changing hands, some of which funds BEST.

I am waiting for Muller to respond that his forecast was a typo, and that he meant degrees Celsius rather than Fahrenheit (the units explicitly used earlier in his op-ed). Even so, he would still come in far below the IPCC, which bills itself as “the consensus of scientists.” Let’s hope he wasn’t that careless.

Welcome to the lukewarm club, Dr. Muller.

Patrick J. Michaels is Director of the Center for the Study of Science at the Cato Institute.