In June, Lyft joined a coalition of 902 businesses, nine states, and 125 cities in formally agreeing to uphold the Paris Agreement, regardless of President Donald Trump's decision to withdraw the US from the commitment.

Now Lyft has outlined its plan to uphold the climate deal, saying its efforts will reduce emissions for the transportation sector by at least 5 million tons per year. Lyft's plan relies on launching a fleet of electric, self-driving vehicles on a mass scale.

To begin, the ride-hailing service said all of its electric, autonomous vehicles will only use electricity generated by clean energy sources, starting with its self-driving pilot program that's launching in Boston later this year.

"If the goal here is climate emissions reductions and reaching those targets set by the Paris Agreement, then we not only want to be powering these vehicles with electricity, but we want that electricity to come from renewable clean sources," Emily Castor, Lyft's director of transportation policy, told Business Insider.

Natural gas currently powers 34% of the US' electricity, followed by coal and nuclear power, according to the Washington Post. Castor said Lyft will use Renewable Energy Certificates, a commodity market, to purchase clean power to charge the cars.

Much of the plans' details are still murky. Castor declined to say how many electric vehicles will be used in the Boston pilot and what types of cars it will be using. Lyft also didn't say how many battery-powered, driverless vehicles it ultimately plans to launch on the service by 2025.

The ride-hailing company did say, however, that it ultimately plans to provide 1 billion rides using electric, autonomous vehicles by 2025. General Motors has said it will launch thousands of self-driving, electric Bolts on the Lyft platform in 2018.

General Motors will launch thousands of self-driving Chevy Bolts on the Lyft platform. Hollis Johnson

UC Davis wrote in its 2017 report 'Three Revolutions in Urban Transportation' that a combination of ride-sharing, electrification, and automation are critical to reducing emissions for the transportation sector.

But for these three transit revolutions to really work, people need to be incentivized to carpool.

Lew Fulton, a co-director of the STEPS program at UC Davis' Institute of Transportation Studies (ITP), previously told Business Insider that he fears autonomous vehicles could lead to a rise of single-passenger cars in a ride-hailing setting.

Since self-driving cars will cut ride-hailing costs, there may be little incentive to share with others, which could make traffic worse. Even if Lyft plans to use purely electric cars, worsening traffic contributes to pollution by having other gas- or diesel-powered cars sitting idly on the road.

But Castor said there's still room to differentiate the price of a shared ride, even if autonomous vehicles make rides cheaper. This is especially true for people living in suburban areas who want to use ride-hailing services to get to work or public transit without breaking bank.

"We actually really need the costs to come down in order to have that catalytic impact on reducing car ownership," Castor said.

Lyft Line, the company's carpooling service, is currently available in 15 markets and accounts for 40% of all rides in select markets. Currently, only 22% of Lyft users rely on the service to connect to public transit.

For Lyft to really have an impact on emissions, the company will need to expand and incentivize its carpooling service and work more directly with public transit.

But a focus on electrification is a positive start, especially with Lyft's stance on using "clean" electricity, something Tesla CEO Elon Musk has also committed to.

"Vehicle electrification can cut vehicle energy use and CO2 emissions," UC Davis wrote in its urban transportation report. "However, for electrification to have maximum benefits, power generation must be strongly shifted away from fossil fuels and deeply decarbonized."