By Dr. Robert Thorson

`You think it’s hot here?” That was the title of an August sermon being advertised on a church-front sign in my town. It went up in response to this summer’s month-long heat wave. Remember the clammy humidity? The parched grass? The lethargy?

The preacher’s question, of course, begs another: Where is it hotter?

The first time I drove by the sign, the warm air led me to believe that the hotter place the preacher had in mind was hell. But the next time I drove by the sign, the afternoon heat had reached that of Dante’s inferno, leading me to believe that he was instead sermonizing about Earth’s climatic future.

Good news first.

Climate extremists are becoming marginalized, based on a recent review published in Science magazine. Since 1979, dispassionate climate modelers have been predicting a fairly narrow range of temperature increase, between 2.7 and 8.1 degrees Fahrenheit, in response to a doubling of Earth’s atmospheric carbon dioxide concentration this century. Meanwhile, climate-change alarmists have been predicting that Earth will broil under the greenhouse sun, whereas climate-change contrarians have been insisting that nothing abnormal is going on with Earth’s climate system, or that long-term warming will be negligible.

These extreme, politically motivated points of view are being silenced by recent independent climate experiments that are more complex and better calibrated than their predecessors’. We now know that there is a 90 percent probability that globally averaged warming will fall within the long-predicted range. In fact, an even newer and more improved modeling experiment suggests that globally averaged warming will be between 4.3 and 9.7 degrees, with a best estimate at 5.8.

Ding dong, the extremists are dead. The average heat for southern New England will not become that of south Florida or Jamaica. Think Virginia instead. Broadly speaking — and using latitude as a surrogate for the estimated temperature rise — the warmth of the mid-Atlantic states will replace that of New England, which will replace that of the Canadian Maritimes.

Now the bad news.

The hotter end of the predicted heat range is far less certain than its cooler end. Scientists are almost certain that Earth will warm up at least 2.7 degrees, quite likely by 5.4. But they are far less certain that 7 to 10 degrees is an upper limit; some models exceed 18 for extreme cases. These higher estimates are being raised primarily by those who study ancient climates using the fossil record (paleo-climatologists), rather than those who tinker with the present climate using numerical simulations of the atmosphere based on its physics and chemistry (climate modelers). Dinosaur bones, for example, have been found in both the Arctic and the Antarctic.

Now the opinion.

Ostrich! Pull your head up out of the sand. Climate change is rolling in for sure, along with untold environmental repercussions. Chicken Little! Stop running around proclaiming that the sky is falling. You will suffer the heat for sure, but it will not be calamitous. Birds of a feather in the middle! Flock together.

Extremist rhetoric is passe. The sermon “God loves you, he maketh the world perfect” may be comforting to the most conservatively minded, but doubters are advised to keep a watchful eye on their thermometers. The sermon “Repent, or you will burn in the fires of greenhouse heat” may jumpstart a few souls toward energy conservation, but more cautious listeners will likely hear the alarmist rant for what it is.

Those of us in the middle — from libertarian to socialist, from poet to engineer, from casino tycoon to hotel maid — must acknowledge that the climate is warming steadily and that it will change the way we live. Rather than beat up on each other about the sin and guilt of energy gluttony, we must learn to adjust and adapt to the coming changes. We must flock together to develop and support government policies that reduce global dependency on fossil fuels, ensure the reliable flow of electricity needed for air conditioning, prepare for an increase in heat-related illnesses and monitor the inevitable transformations of our ecosystems.