The trouble with paper bags: carbon emissions

So does that mean paper bags, which degrade more easily, are a better option? Not necessarily. Climate change has become the biggest environmental issue of our time, so it’s worth looking at things from an emissions standpoint. And on that score, paper bags fare worse.

Even though paper bags are made from trees, which are, in theory, a renewable resource, it takes significantly more energy to create pulp and manufacture a paper bag than it does to make a single-use plastic bag from oil.

Back in 2011, Britain’s Environment Agency conducted a life-cycle assessment of various bag options, looking at every step of the production process. The conclusion? You’d have to reuse a paper bag at least three times before its environmental impact equaled that of a high-density polyethylene plastic bag used only once. And if plastic bags were reused repeatedly, they looked even better.

Paper bags can more easily be recycled or even composted, bu t the British study found that even these actions didn’t make a huge difference in the broader analysis. Unless you’re reusing your paper bags a lot, they look like a poorer option from a global warming standpoint.

Reusable bags are a decent option — if you actually reuse them

That same British analysis also looked into reusable options, like heavier, more durable plastic bags or cotton bags. And it found that these are only sustainable options if you use them very frequently.

Making a cotton shopping bag is hardly cost-free. Growing cotton requires a fair bit of energy, land, fertilizer and pesticides, which can have all sorts of environmental effects — from greenhouse gas emissions to nitrogen pollution in waterways.