The world runs on bad luck. Call it Erskine’s Law.

There was a pair of Canada geese on the quad the other day. Lovers, probably. You could see it in the way she undressed him with her eyes.

We don’t see many of the big, pewter birds here. The two lovers were likely migrating south to north, though it seems a little early for that. I mean, who goes to Alberta in early March? The emergency stash of Dewar’s is already gone. Gordon Lightfoot is still buried under 140 feet of snow.

As is often noted, Mother Nature has lost her mojo. Maybe she was downsized or retired. In any case, the natural world she oversees seems grossly out of sync.

Of course, this is not the first time. In the 1930s, the world seemed to be drying up. In the midst of the Great Depression, dust storms made noon look like midnight. The gritty, ghostly clouds moved from the Great Plains to the Midwest. Topsoil from Nebraska was soon sitting atop windowsills in Chicago.

The weather then was so bad that it changed history. Like those Canada geese, families migrated in uncommon patterns, from Oklahoma and Kansas, west to California and the Pacific Northwest. On brittle tires they drove, in a desperate stab to stave off starvation.

And you think you have problems?

As my boss noted the other day, we are quickly losing the sturdy generation that survived all that. The sons and daughters of the Dust Bowl are now in nursing homes or assisted-care facilities in Long Beach or Burbank or wherever they ended up. L.A. was then, as it still is, a promised land full of transplants.

Now the promised land is running out of water. Experts are always saying that “geography is destiny,” but destiny is also weather patterns. In 2005, too much water nearly devoured New Orleans, my favorite city. In the ‘30s, the “black blizzards” of dust drove residents right off the Plains.

Today, the West is sucking dry its aquifers. Where that leaves the nation’s breadbasket is anyone’s guess. But, as in the early days of the Nile Delta and civilization itself, destiny is topsoil and irrigation, as well as geography and weather. Turns out that destiny is a lot of things. Greed and ego too.

The other night, the much-promised rains finally hit the roof. During times of drought, rain on the roof is like nature’s acoustic guitar. I couldn’t sleep for the music of it. It was like standing under a waterfall after a parching hike.

For the last month, the much-vaunted El Niño consisted of a single cloud that passed over our house — I think it was a Tuesday. The sudden shade threw everybody off. Songbirds quit singing; even the leaf blowers stopped their awful barking.

Neighbors came out of their houses to marvel over this miracle. “Look, a cloud!” I said, pointing at the sky. “Can El Niño be far behind?”

It’s not like forecasters to ever get things wrong. Just in case, I put snow chains on the car.

Sure enough, the skies finally opened up a few days later. I like the cozy comforts of a good winter rainstorm — the blankets, the books, a steamy cauldron of soup.

A real rain rinses the grime off the driveway, and it soaks deep beneath the magnolia tree out front, whose roots are eating into our septic tank.

It’s always something, right? If the tree dies, the septic tank lives. If the tree lives, the tank collapses and I’m out another 12 grand I don’t have.

And you think you have problems?

“Symbiosis,” biologists call it, the relationship of one dissimilar thing to another. In fact, according to something called the butterfly effect, the world is so interlaced, that when a butterfly flaps its wings in Tanzania it can trigger a tropical storm in the Cayman Islands weeks later.

I like the romance of that, the gossamer delicacy, the godly notion that we’re all in this together. But is the concept of the butterfly really science? Or, as with many theories, an attractive mythology?

To me, the world seems more based on bad luck.

I’d offer a corollary to the butterfly effect. Call it Erskine’s Law.

According to Erskine’s Law, if you wash your car it will rain. If you replace the roof, you will trigger a 20-year drought. If you plant a tree, it will eat the septic system.

Under Erskine’s Law, when a beautiful butterfly flaps its wings over some river in Tanzania, it’ll immediately be eaten by a goose.

chris.erskine@latimes.com

Twitter: @erskinetimes