Each additional metric ton of carbon dioxide or its equivalent — your share of the emissions on a cross-country flight one-way from New York to Los Angeles — shrinks the summer sea ice cover by 3 square meters, or 32 square feet, the authors, Dirk Notz and Julienne Stroeve, found.

In February, my family of three flew from New York to Miami for what seemed like a pretty modest winter vacation. An online carbon calculator tells me that our seats generated the equivalent of 2.4 metric tons of carbon dioxide.

Throw in another quarter-ton for the 600 miles of driving we squeezed in and a bit for the snorkeling trip and the heated pool at the funky trailer-park Airbnb, and the bill comes to about 90 square feet of Arctic ice, an area about the size of a pickup truck.

When I did that calculation,

I pictured myself standing on a pickup-truck-sized sheet of ice as it broke apart and plunged me into frigid waters. A polar bear glared hungrily at me.

Andy Newman, journalist