SACRAMENTO — Gov. Jerry Brown says California needs to eliminate plastic that people use once and throw away, and on Thursday he took a step in that direction — signing a bill that makes the state the first in the U.S. to ban restaurants from handing out plastic straws unless a customer asks for one.

Brown and other supporters acknowledged that the law, which takes effect Jan. 1, is limited in its scope. It applies only to dine-in restaurants and exempts the biggest sources of straw pollution — fast-food restaurants, delicatessens, coffee stores and any other outlet that supplies takeout orders.

But in his signing message, the governor argued that the law’s limited impact is a point in its favor — that it might spur Californians to limit their plastic consumption on their own, without the state having to mandate it.

“It is a very small step to make a customer who wants a plastic straw ask for it,” Brown said. “And it might make them pause and think again about an alternative. But one thing is clear, we must find ways to reduce and eventually eliminate single-use plastic products.”

Brown railed against the overuse of plastic, which was invented in the late 19th century and has “become so ubiquitous it now pervades every aspect of our modern life.”

“It is even found in toothpaste,” the governor said. “Plastic has helped advance innovation in our society, but our infatuation with single-use convenience has led to disastrous consequences.”

Plastic straws and stirrers are the sixth most common type of litter on state beaches, according to logs from the California Coastal Commission’s annual coastal cleanup days. Conservation groups say the plastic trash that flows out of urban storm drains is threatening the habitat of 500 species of wildlife, including 23 endangered species, in San Francisco Bay alone. Marine biologists say fish and birds often ingest pieces of plastic that they mistake for food.

Brown pointed to reports of 80 plastic bags found in the stomach of a whale that died in Thailand.

“Plastics, in all forms — straws, bottles, packaging, bags, etc. — are choking our planet,” Brown wrote.

California banned single-use plastic bags in 2016. The groups that supported that law have now turned their attention to single-use plastic straws.

Plastic straws were first used in the early 1960s, and by the ’70s they had largely replaced paper straws. The anti-straw lobby has pushed restaurants to switch back to paper or encourage customers to buy reusable straws made of stainless steel, glass or bamboo.

Some cities have already adopted restrictions on plastic straws, including San Francisco, Alameda, Oakland, Richmond, Berkeley, Carmel, San Luis Obispo and Davis.

Starbucks announced in July that it would remove plastic straws from all its stores — not just in California — by 2020.

Simply barring dine-in restaurants from giving straws to customers whether they ask for them or not won’t cut litter significantly, according to a legislative analysis of the bill Brown signed, AB1884 by Assemblyman Ian Calderon, D-Whittier (Los Angeles County). The analysis also concluded that the bill is unlikely to “change consumer behavior.”

Many Republicans voted against the bill, calling it empty symbolism.

“I just don’t see how this is going to make that much of a difference in reducing the amount of straws in the waterways,” Assemblywoman Melissa Melendez, R-Lake Elsinore (Riverside County), said before the bill passed the Legislature. “I think an education campaign makes sense for sure, and I think an incentive-based program makes even more sense.”

Environmental groups disagree, saying the law is a solid first step.

“We want people to avoid creating plastic waste whenever possible, because it’s an epidemic in our cities and in the bay,” said David Lewis, executive director of the conservation group Save the Bay. “People who really need a straw can still get one.”

The bill got off to a rocky start when it was introduced in January, because it called for waiters to face a maximum $1,000 fine and six months in jail for handing out straws without being asked. Those penalties were quickly removed from the bill and replaced with two warnings, followed by a $25-per-day fine to the restaurant, with a maximum of $300 a year.

After that, AB1884 received little opposition, with the plastic industry and restaurant associations both neutral on the bill.

Gwyneth Borden, executive director of the Golden Gate Restaurant Association, said that “most restaurants and bars have already started to move in the direction of only offering plastic straws upon request, and some have only been offering paper straws.”

The problem, she said, is that it is now hard to get paper straws because of the demand.

“There is a massive shortage,” Borden said. “Obviously with a shortage of supply, paper straw prices are going to go up.”

Borden said it would be nice if legislators went after manufacturers instead of restaurants.

“Yes, this is a victory for the environment,” she said. But “why do they always go after the business and not manufacturers who have control over the cost? I think government leaders should be more creative on how they make the industry supply the product. When you make legislation that impacts the supply side, consumers and businesses end up paying more.”

Mark Murray, executive director of Californians Against Waste, said that with the bill’s signing, Brown sent a message that the state will lead efforts to reduce plastic waste.

“From eliminating nonrecyclable plastic food packaging at state facilities to reducing the proliferation of single-use plastic straws, California is putting the brakes on these unnecessary sources of plastic pollution,” Murray said.

Melody Gutierrez and Peter Fimrite are San Francisco Chronicle staff writers. Email: mgutierrez@sfchronicle.com, pfimrite@sfchronicle.com Twitter: @MelodyGutierrez, @pfimrite