Are pet dogs and cats bad for the environment?

Our dogs and cats provide all kinds of benefits. They improve physical health, reduce stress and can fend off loneliness.

- Rachel Nuwer

NEW YORK -

Research shows that interacting with pets can lower blood pressure. Dogs need walks and playtime, which helps people stay active. And both dogs and cats can form deep bonds with humans. Basically, they enrich people's lives.

"There's a whole body of literature supporting that," said Mr. Pieter De Frenne, a bioscience engineer at Ghent University in Belgium.

Yet for all the good, pets come with environmental costs. Cats and dogs eat a lot of meat, for example. They also kill wildlife.

So, how can you get all those tangible and intangible benefits and keep the environmental pawprint as low as possible? Here is what the experts have to say.

A WHOLE LOT OF MEAT Mr. Gregory Okin, a geographer at the University of California, Los Angeles, calculated in a 2017 study that the estimated 163 million cats and dogs in the United States consume a whopping quarter of the country's animal-derived calories.

"If U.S. dogs and cats were their own country, they would rank fifth in global meat consumption," he said in an interview.

Pet food, Mr. Okin estimated, accounts for about a quarter of agriculture-related fossil fuel emissions in the U.S. Globally, another study found that dry pet food was responsible for up to 2.9 percent of carbon dioxide emissions from agriculture and 1.2 percent of agricultural land use.