California is not only the Golden State but also, at least unofficially, the Bellwether State. While it is the last place on the continent that the sun touches, it is often the first place social trends are illuminated. The latest has some people hot and bothered.

Last week, Govenor Jerry Brown signed a bill to make California the first state to ban single-use plastic bags at supermarkets and pharmacies beginning July 2015, although it does not apply to bags used for fruits, vegetables or meats. The prohibition will extend to convenience stores, liquor outlets and small food stores in July 2016. Where California leads, other states may follow.

This is not lost on plastic bag manufacturers. The American Progressive Bag Alliance, an industry coalition, is warning of dire job losses and promises to seek a voter referendum to overturn the ban. Because the law proposes that grocers charge a 10-cent fee for paper bags, paper bag manufacturers are against it, too.

But there’s a good reason for the ban. Plastic bags used for groceries are a major source of pollution, both on land and in the sea, where they are a threat to marine life. In landfills, they take hundreds of years to biodegrade.

Plastic bags do have their uses and can be recycled. Newspapers are sometimes delivered in them to keep the product dry and those bags often find a second beneficial use when dog owners pick up after their pets. However, by sheer weight of numbers, plastic bags distributed in grocery stores are the main pollution problem.

The environmental benefit to replacing plastic bags in supermarkets is widely acknowledged. This is why many stores already ask customers “Paper or plastic?” or, better yet, urge shoppers to bring their own reusable bags from home, which is the real intent of the California law.

It is not much to ask of a responsible citizenry.

Anybody who deplores the overreach of big government in California will have it backward. Before this bill passed in Sacramento, dozens of municipal governments had passed their own bans, expressing the will of their constituents. It seems that the more scenic a place is, like Carmel, California, or Nantucket Island, Massachusetts, the more people understand the environmental benefit of such a ban.