Why would anyone carry a single-use plastic bag? We’ve all seen the disheartening photos of plastic trash strewn across beaches and oceans. The hundreds of American municipalities that have banned or restricted single-use plastic bags are thus saving the waterways and making us a more eco-friendly society — right?

Well, maybe not. John Tierney, a contrarian who has written extensively about politicized science, makes a compelling case that everything we know about single-use plastic bags is either misguided or wrong.

For example: “Environmentalists frequently claim that 80 percent of plastic in the oceans comes from land-based sources, but a team of scientists from four continents reported in 2018 that more than half of the plastic from the ‘Great Pacific Garbage Patch’ came from fishing boats — mostly discarded nets and other gear.”

It’s also worth noting that, “Of the plastic carried into oceans by rivers, a 2017 study in Nature Communications estimated 86 percent comes from Asia and virtually all the rest from Africa and South America.”

Some of what ends up in the ocean, Tierney explains, actually started out as plastic recycling, which often proves too expensive to sort and clean, so it’s shipped to countries such as Thailand, Malaysia, Vietnam, and Indonesia. Those countries frequently discard the plastic rather than reuse it, a phenomenon known as “mismanaged waste.”

If Americans want to reduce both plastic pollution and carbon emissions, Tierney lists a handful of actions we should take:

“Stop exporting plastic waste to countries that allow it to leak into the ocean. Help those countries establish modern systems collecting and processing their own plastic waste. Send plastic waste straight to landfills and incinerators. Step up enforcement of laws and treaties that restrict nations from polluting the ocean and prohibit mariners from littering the seas.”

Repealing plastic-bag bans would also help, Tierney writes, since thin plastic bags require less energy to make than the bulkier bags many of us lug to the grocery store. They also take up less space in landfills and, unlike paper and cotton bags, don’t release greenhouse gases once discarded: “The plastic bags’ tiny quantity of carbon, extracted from natural gas, goes back underground, where it can be safely sequestered from the atmosphere and ocean in a modern landfill with a sturdy lining.”

It’s truly a fascinating piece. Check out the whole thing in City Journal or read an excerpt in the Wall Street Journal.