At a time when there’s so much to worry about — global war, the long-range forecast, the coming shortage of citrus fruit — it seems almost silly to mention the one threat that causes us most to get hot under the collar.

But here is it: the thermostat.

As outdoor temperatures crashed this week, the Hansons’ silent battle for the perfect indoor climate heated up all over again. Not since the heat of last summer has control of our indoor environment caused such serious discord at our normally serene address. But, once again, modern technology and the surreptitious urge to dominate have now brought us to the edge of passive-aggressive Armageddon.

Ground Zero is the dimly lit hallway where the thermostat quietly resides. It’s out of sight from every other corner. Yet whenever Russ or I come near, the whole house begins to sizzle or shiver from guerilla attacks to enforce our very different notions of the ideal indoor habitat.

You could say the difference is just a matter of degree. Russ regards the great indoors as an extension of his body temp. When he comes inside, chilled after hours of fiddling with the timer on the porch lights, he’s no sooner taken off his gloves than he dials up the thermostat to warm his frigid bones.

Like many human males, he considers the furnace as a sort of full-body electric blanket. This differs just a tad from his wife’s position — that our indoor environment is a giant, energy-sucking black hole into which we pour our monthly tithe to Moorhead Public Service.

I attribute our differences to the way that we were raised. He grew up in urban Bismarck-Mandan, where MDU piped natural gas, sight unseen, straight into his childhood domicile. I, on the other hand, learned the ways of the world one floor above the family coal bin.

If you, too, grew up in a house heated by coal, you remember the roar of a ton of dusty black bituminous tumbling down the chute to the basement. There it waited, dark and sulfurous, for Dad’s periodic trips into the stone-walled cellar to feed the roaring beast — the coal furnace, where the flames of hell danced and leaped behind the little glass porthole in the door.

The mere notion of a wall-mounted dial to control the heat was as space-agey as the Jetsons. If December winds rattled the single-paned windows on the northwest side of the house, he trekked into the shadowy cellar to stoke the fire and feed it shovelfuls of black chunks, ranging from the size of your head to the dust in the bottom of your pockets. He’d fish out the burned-out clinkers, still aglow, with long-handled tongs. At bedtime, he’d make a last trip to bank the fire and throttle the oxygen that fed it … then stir it up at dawn.

More sophisticated systems employed the flames to heat water in a boiler, which then circulated through radiators strategically stationed throughout the house. Radiators were a wonder: a modern convenience on which both snowy mittens and dampened dishtowels would dry in a flash, and which warmed many a chilled young backside fresh from a frigid sledding expedition.

Our house wasn’t that ultramodern. Instead, our coal furnace relied on the most basic of scientific verities: Heat rises. The coal-fired warmth rose through a register on the main floor, then continued upward to where the chilly bedrooms waited. No sissy thermostats reined in the scorching heat of a freshly fed fire or spurred the furnace to accelerate all on its own. Nor did the firepit let us forget its contributions. A backdraft of smoke, a dusting of soot, the vague perfume of sulfur — all reminded us from time to time of just who, or what, kept the North Country’s fierce wolfish winds at bay.

Childhood taught me climate control was very much a manual art. Too hot? Sit farther from the register. Too cold? Put on a sweater. They were the same hardy lessons that Laura Ingalls Wilder had written about scores of years before, still prevailing in the 1950s in our own little house on the prairie.

Today’s environmental give-and-take relies more on psychology than on the conscious effort of days of yore. At our house, it usually takes the form of guerilla incursions on the thermostat. Rather than adding or subtracting a layer of clothing, personal comfort too often relies on sidling past the dial, all innocent, and giving it an unannounced tweak.

If I hear the fan lurch up to speed, I can calculate Russ’s whereabouts with some precision. He’d tell you that he knows who’s been afoot when he spots ice forming on the kitties’ water dish.

Our seasonal psychological warfare generally lasts until the annual spring armistice. But it’s to no one’s real surprise that incursions resume as the mercury rises in midsummer. Then, though, it’s the sweaty husband who twirls the frosty thermostat ever lower … and the cold-hearted, cost-conscious wife who’s guaranteed to get hot under the collar.