A driver takes the wheel of a self-driving Uber car last September in Pittsburgh. (Angelo Merendino/AFP/Getty Images)

The rise of the sharing economy — via Uber, Craigslist, Airbnb and other platforms — could help reduce the climate impact of dense urban areas, a new study suggests.

Cities produce a rising share of the global greenhouse-gas emissions that cause climate change.

Over the past 50 years, the trend to smaller households — singles, or couples with no children — has helped push emissions upward in cities and rural areas. Smaller households produce a disproportionate share of emissions compared with families.

Larger households that pool resources, or share, a car, air conditioning or washing machine tend to have a lower carbon footprint because they are not duplicating climate-altering activities.

Think of the sharing economy, then, as a scaled-up version of a large family home, where everyone watches the same television, does their laundry together, shares meals and rides in the same car, a paper published in Ecological Economics suggests.

From calling an Uber to using public parks and libraries, shared resources can cut down on individual energy consumption and help to tackle climate change, the researchers found.

“Within cities and dense urban areas, people are able to share carbon-intensive goods,” Anders Fremstad of Colorado State University, co-author of the paper, told The Washington Post in an interview. “. . . Increasingly today, we have peer-to-peer platforms like Uber, Airbnb and Craigslist.”

Sharing has always had benefits, the researchers pointed out, but over time the opportunities have become more obvious.

If everything else had remained constant, per-capita U.S. emissions would have increased by about 9 percent between 1960 and 2010 — solely because of diminishing household size, according to the study.

Since 1960, the percentage of one-person households in the U.S. has doubled to 27 percent from 13 percent, as people wait longer to get married or have children. Nearly half of the homes in Manhattan are occupied by a single person.

But shared services in urban environments have helped offset the potential increase in greenhouse-gas emissions by about 3 percent since 1960, the study found.

Historically, the study said, large households in which everyone shares appliances have helped limit emissions. Adding another person to a household reduces everyone else’s personal emissions by about 6 percent, the study found.

The findings offer some encouraging news with the expansion of a sharing economy through apps such as Uber and Airbnb.

The carbon benefits of these online sharing networks are an argument for more digitally connected cities, the researchers said. They argued that equipping more public spaces with WiFi would increase access to these online platforms and therefore help to reduce emissions.

But the researchers had some caveats.

Mobile apps alone are not going to solve climate change. Most of the emissions reductions will come from the intense use of shared infrastructure, including public transport, shared heating and cooling in apartment blocks, and public parks and libraries.

“There’s a lot of excitement around the sharing economy, and I’m excited, too, but it’s important to recognize that people have been sharing things forever,” Fremstad said.

“The magnitude of the environmental benefits is much larger for some of these older institutions than it is for the newer ones so far,” he said. “We don’t need to get rid of the libraries yet!”

And the researchers warned that the rise of sharing networks could cause more damage than good to the planet without stricter regulations.

While UberPool can help to cut back on taxi rides, it could also lead to people using small vehicles rather than public transport. Similarly, Airbnb could increase the use of electricity and gas in houses that would have otherwise been left vacant.

“The sharing economy and peer-to-peer platforms can be set up in a way that they incentivize this simultaneous sharing of resources and can drive down emissions, and I think it can be a good thing for sustainable cities,” paper co-author Anthony Underwood of Dickinson College said in an interview with The Post — but he stressed that the right policies and regulations must be in place.

Another drawback for the planet could be the money saved by sharing. If the additional wealth is spent on other carbon-intensive products, such as flights or a second home, then the carbon benefits could be reduced, the researchers said.

The findings contradict the notion that population growth is one of the key drivers of climate change, a notion that gained further currency recently after a study claiming that having one fewer child is the most effective way to reduce your emissions.

“The size of the population matters, but the composition of the population is way more important,” Underwood said.

It would be possible for 100 people living in large family homes to emit less than 50 people who live alone, he concluded.