With more cities, states and countries banning single-use plastic bags, paper has become a popular alternative at the grocery checkout. At first glance, this seems like an obvious win for the environment. Plastic bags, after all, are made from fossil fuels and a major source of pollution.

Paper bags, however, are not necessarily a better choice. They come with their own list of environmental caveats, as do reusable totes.

Here are some of the things to keep in mind for making an informed decision about bagging your groceries.

Plastic and paper

It’s hard to make apples-to-apples comparisons, pun intended, of different kinds of grocery bags. That’s because a bag’s environmental footprint depends on a plethora of factors: how it was made, what materials were used, how far it was transported and much more. But the few thorough studies that have been done on the subject do offer some helpful takeaways.

Paper bags tend to require more energy to produce than plastic ones. A 2011 study by Britain’s Environment Agency, for example, concluded that you’d have to reuse a paper bag three times to bring its global warming impact in line with that of a plastic bag used just once.

A 2018 study by Denmark’s Environmental Protection Agency similarly found that plastic bags made from low-density polyethylene, a versatile and widely used form of plastic, have the smallest environmental footprint of eight types of grocery bags, including paper ones.