U.S. President Barack Obama speaks during a press conference at the OECD Conference Center, Dec. 1, 2015, before leaving the U.N. climate change conference in Paris. Pascal Le Segretain/Getty Images

Major U.S. corporations are throwing their support behind an aggressive global treaty to cut greenhouse gas emissions. More than 70 companies, from 21st Century Fox to to American Honda Motor, signed a White House pledge this week as negotiators from around the world arrived in Paris for United Nations-led climate change talks, the Obama administration said Tuesday.

The latest addition nearly doubles the number of firms to sign the American Business Act on Climate Pledge, which was launched in June. The 154 signatories together employ nearly 11 million people and represent more than $4.2 trillion in annual revenue, according to the White House.

President Barack Obama was in Paris this week for the start of the two-week summit, where leaders from nearly 200 countries will work to reach a universal agreement. Part of the president's climate push includes rallying support from the U.S. business sector. This summer, several U.S. companies, including Apple, Google, Microsoft and Bank of America, announced at least $140 billion in new investments to lower their carbon emissions and boost funding for clean energy -- part of a separate White House effort to recruit private companies in the fight against climate change.

The companies that signed the American Business Act on Climate Pledge Tuesday voiced support for a strong outcome in Paris, the White House said in a news release. The firms also agreed to support any emissions-cutting deal by setting targets to reduce their own corporate emissions, increase investments in low-carbon technologies and take other actions to build more sustainable businesses.

Mass media giant 21st Century Fox, for instance, said it would reduce carbon emissions by 25 percent compared with 2013, normalized by revenue, as well as slash emissions from Fox feature film productions by 15 percent per day of filming. Amazon restated its goal to use 100 percent renewable energy to power its Amazon Web Services division. By next year, the company expects to get 40 percent of the division’s power from solar, wind and other clean energy sources.

Rio Tinto Group, a British-Australian mining giant with U.S. coal operations, said in the White House pledge that Rio Tinto “recognizes climate change is occurring and is largely caused by human activities.” The conglomerate vowed to seek a “substantial decarbonization” of its business by 2050 and work to reduce emissions in its business operations.

Atmospheric Carbon Dioxide Concentration (1958 - Present) | WeatherDB

“No corner of the planet and no sector of the global economy will remain unaffected by climate change in the years ahead,” the White House said.

Obama delivered an optimistic speech in Paris Tuesday, saying he expected the gathered countries could accomplish their goals.

“All of this will be hard -- getting 200 nations to agree on anything is hard,” he said. “This is an economic and security priority that we have to tackle now. And great nations can handle a lot at once.” He added, “My main focus is making sure that the United States is a leader in bringing a successful agreement home.”