In a rare show of solidarity, American automakers and the unions representing their employees are begging the Biden administration to back off on its aggressive efforts to force Americans into electric vehicles in the name of combating climate change.

Leaders of the United Auto Workers union asked President Biden’s Environmental Protection Agency to water down a proposal to make upcoming emissions standards for internal combustion engines much stricter by 2027. The new standards would effectively require that two-thirds of all vehicles sold in the United States be electric by 2032.

In a letter to the agency, the union said the new rules are not practical given current market conditions and should be phased in over a longer period of time. Nearly 60 percent of all union-made vehicles in America are currently light trucks and SUVs.

“We fear the proposed standards are premature and risk disrupting the market that will make the EV transition possible,” the UAW said. “We urge EPA to continue to work with all key stakeholders to ensure the new rules do not disproportionately impact domestic union auto production.”

The automakers have already warned in comments to the EPA that the new standards are not feasible. A group representing most major automakers other than Tesla, the Alliance for Automotive Innovation, called the new standards a “de-facto battery electric vehicle mandate” backed only by “rosy forecasts and other hopeful assumptions.”

“EPA’s standards cannot be met without substantially increasing the cost of all vehicles, reducing consumer choice and disadvantaging major portions of the U.S. population and territory,” the group said.

The joint criticism comes just days before contract talks between the UAW and Detroit’s big three automakers — Chrysler’s parent, Stellantis, plus Ford and GM — are set to begin later this week. One of the main sticking points is expected to be the carmakers’ efforts to pare costs in order to comply with federal mandates targeting electric vehicles.

Analysts say the automakers are losing billions of dollars producing electric cars that customers, so far, are not eager to drive off the dealers’ lots. A recent mid-year report from Cox Automotive said consumers are slowly coming around to electric cars — 6.5 percent of the domestic market is currently electric, and more than a million units are expected to sell this year for the first time — but production is now far outpacing demand.

Cox’s report said there are currently 90,000 electric vehicles sitting on dealer lots, a figure that amounts to 92 days’ worth of unsold inventory and is a four-fold increase from last year. The same figure for all vehicles is closer to 51 days. Generous discounts from the industry’s leader, Tesla, which has 60 percent of the market share, are cutting into sales of the other companies’ vehicles, according to Cox.

The lackluster sales come despite aggressive subsidies for electric vehicle adopters courtesy of American taxpayers. In his so-called Inflation Reduction Act of 2022, Mr. Biden signed off on tax credits worth up to $7,500 for consumers who purchase electric vehicles made in America as well as billions more for battery production projects.

The UAW is one of the few unions in America that has not endorsed Mr. Biden for president in 2024, and the union says it is primarily because of his electric vehicle policies. In a memo to union members last month, the UAW’s new president, Shawn Fain, said the White House needs to ensure that the EV subsidies are going to support high-paying jobs with security.

“We’ll stand with whoever stands with our members in that fight,” Mr. Fain wrote. “The federal government is pouring billions into the electric vehicle transition, with no strings attached and no commitment” to automakers’ employees, he said. “We want to see national leadership have our back on this before we make any commitments.”

In polling released in April, only 19 percent of Americans said it was “very” or “extremely” likely that they would buy an electric car for their next vehicle purchase, and 22 percent said it was somewhat likely. Just less than half — 47 percent — reported that they weren’t likely to go electric at all.

High cost was a major reason cited by six in 10 poll respondents, and a minor reason for about a quarter of those polled by the Associated Press-NORC Center for Public Affairs Research and the Energy Policy Institute at the University of Chicago. The survey, the AP reported, “shows that the Biden administration’s plans to dramatically raise EV sales could run into resistance from consumers.”