Facebook will likely end its relationship with a controversial conservative policy organization, The Chronicle learned Tuesday.

The social media giant in Menlo Park would be the second Silicon Valley giant in recent days to sever ties with the American Legislative Exchange Council, known as ALEC. On Monday, Google Chairman Eric Schmidt told a radio show that the company would end its membership with the group over its stance on global warming.

ALEC was “literally lying” about climate change, Schmidt said.

Silicon Valley firms, which are relatively new to politics, have supported both liberal and conservative candidates and groups. But public pressure on such issues as global warming is forcing tech companies to rethink their strategies.

On Tuesday, national and world leaders including President Obama and Gov. Jerry Brown gathered in New York for a United Nations summit on reducing carbon emissions. The summit follows massive protest in New York that drew more than 300,000 people.

For several years, climate activists have urged tech companies and other corporations to cut ties with ALEC. The lobbying organization, which counts Exxon, Koch Industries and other major fossil fuel companies among its more than 300 corporate and 2,000 legislative members, writes pro-business legislation on a variety of issues, including energy. ALEC then reintroduces the “model” bills elsewhere.

Across the country, ALEC-written measures have attempted to roll back existing protections on environmental, labor, civil rights and public health laws. The less government intervention in business, the better, ALEC believes. It also helped craft the “stand your ground” law in Florida that drew nationwide attention after teenager Trayvon Martin was shot to death.

However, railing against ALEC has been largely confined to wonks and progressive activists, whose pressure campaigns over the past three years have nonetheless helped to persuade companies including Coca-Cola, Kraft, General Electric and General Motors to leave the group. In August, Microsoft ended its membership with the organization, but did not explicitly say it was over environmental issues.

Schmidt, however, was much more direct Monday while appearing on Diane Rehm’s syndicated call-in radio show. In responding to a caller’s question about why the company was affiliated with ALEC, Schmidt said that Google joined ALEC for an unrelated political issue that he did not identify. But now, he said the company formed a consensus that the affiliation was “a mistake.”

“Everyone understands climate change is occurring and the people who oppose it are really hurting our children and our grandchildren and making the world a much worse place,” Schmidt told Rehm. “And so we should not be aligned with such people — they’re just, they’re just literally lying.”

Google’s shift comes after intense lobbying over climate change and dire predictions about the planet’s health in recent days.

On Sunday, an international team of scientists with the Global Carbon Project reported the world pumped 2.3 percent more carbon emissions into the world last year than in 2012. Last week, scientists with the National Climatic Data Center reported that 2014 was the hottest summer since records began being kept more than a century ago.

ALEC’s executive director, Lisa B. Nelson, said “it is unfortunate to learn Google has ended its membership in the American Legislative Exchange Council as a result of public pressure from left-leaning individuals and organizations who intentionally confuse free market policy perspectives for climate change denial.”

Nelson said Google and other companies recently participated in a roundtable discussion on renewable energy and climate change during ALEC’s annual meeting in Dallas. The hope, Nelson said, was that the participants “could find common ground on issues of climate change, energy generation and government mandates. And, I personally intend to continue this work.”

Google has been feeling the heat on this issue for a while.

The environmental organization Forecast the Facts recently called out a number of corporations — including Google — for talking a good game on climate change, but then contributing a combined $641 million since 2008 to a list of 160 “climate deniers” in Congress. The organization said that while Schmidt personally is a forceful climate advocate, Google employees and the corporation’s political action committee had contributed $699,195 since 2008 to members of the “climate denier caucus” in Washington — their name for politicians who oppose regulations to curb emissions.

Now, given Google’s influence as one of the nation’s most valuable companies, environmentalists hope that Google will inspire an avalanche of other tech firms to leave ALEC.

“It’s an indication that climate deniers are the new tobacco executives,” Michael Brune, executive director of the Sierra Club, told The Chronicle on Tuesday. “Nobody wants to be seen with them.”

“Members of the Sierra Club and other activists are going torank and spank the rest of the industry,” Brune said. “You just can’t have leading technology firms continuing to associate with groups like ALEC who are holding back progress on climate change. ALEC is on the wrong side of almost every piece of climate legislation across the country.”

Google’s departure “really puts Facebook and Yahoo in an uncomfortable position,” said Jay Riestenberg, a research analyst with Common Cause who follows ALEC.

Facebook may be next out the ALEC door, a company spokesperson told The Chronicle on Tuesday.

“We re-evaluate our memberships on an annual basis and are in that process now,” a company representative wrote in an e-mail to the newspaper. “While we have tried to work within ALEC to bring that organization closer to our view on some key issues, it seems unlikely that we will make sufficient progress so we are not likely to renew our membership in 2015.”

Earlier this year, Yahoo said as part of its “commitment to being an environmentally responsible company, our goal is to source 50 percent of our annual electricity from on-site generation.”

But on Tuesday, a Yahoo spokesperson said that “at this time, we are members of ALEC and limit our engagement to their Communications and Technology Task Force.” Like many companies that are members of ALEC, the company works with the organization on a number of issues besides energy.

“At Yahoo, we engage in the political process in a variety of ways to promote and to protect the long-term interests of our users and our company,” the company said in a e-mail. “One of the ways we do so is is through memberships in organizations that help advance our business objectives. We may not agree with all the positions of an organization, its leaders or its supporters.”

The Sierra Club’s Brune said there is a disconnect between what many tech companies believe about climate change and how their corporate parents behave politically.

“If you look at most of the employees in these companies — these are smart people who believe in climate science and they believe in clean energy technology,” Brune said. “And yet some of the institutions that their companies associate with are knuckle-dragging climate deniers. The government affairs office isn’t coordinating with the executive office.”

Joe Garofoli is a San Francisco Chronicle staff writer. E-mail: jgarofoli@sfchronicle.com Twitter: @joegarofoli