Indeed. I plugged in numbers from a carbon-footprint calculator and … no, that couldn’t be right. But I kept doing the math and kept getting the same answer: My family’s one-week winter-break trip to Florida would shrink the ice cover by 90 square feet.

By this point, we had already decided to go to Greece for summer vacation, a far more destructive journey. I felt compelled to mention this, too, at the end of the article. I could not think of anything to say about it other than that we planned to buy carbon offsets to counteract the effects of our flights, and hope for the best.

The article was published on June 3. A lot of readers were furious when they got to the end.

“You are literally performing the cop-out that your article purports to critique,” someone wrote on Twitter.

“You’ve broken my heart,” someone else wrote, “knowing full well the consequences and yet still choosing personal gratification over the hope that your ‘sacrifice’ will help as every small action adds up.”

Other readers, conversely, were irked that I was focusing on individual travel at all. They said I was letting big corporations and governments off the hook for their refusal to make huge across-the-board changes to stop global warming.

In any case, I have kept my word. Last week, I went to the website of a nonprofit called Cool Effect that sells offsets and gave it $168 to support a project to install biogas digesters in households in China and Vietnam.

A biogas digester is basically a vat with a pipe attached to it. You put manure — cow, pig, human, whatever — and water in it. As the manure decomposes, it releases methane, a greenhouse gas far more destructive than carbon dioxide. The pipe connects to your cookstove, and you cook with the methane — burning it off pollutes much less than just releasing it, and much less than burning coal or wood.