More than 600 U.S. companies and investors have signed an open letter asking President-elect Donald Trump and other political leaders to support policies and investments in a low-carbon future. They also urged Trump to keep America in the Paris climate agreement.

"We want the U.S. economy to be energy efficient and powered by low-carbon energy," the letter said. "Cost-effective and innovative solutions can help us achieve these objectives. Failure to build a low-carbon economy puts American prosperity at risk. But the right action now will create jobs and boost U.S. competitiveness."

The letter was first signed by about 360 companies—including ebay, Starbucks and Unilever—shortly after the November election. Since then, however, participation has nearly doubled, organizers said Tuesday.

The letter was orchestrated by Ceres, the World Wildlife Fund and six other sustainability and environmental groups. It has now been signed by more than 530 companies, including Allianz, Johnson & Johnson and SolarCity. Collectively, these businesses have nearly $1.15 trillion in annual revenue, are located across 44 states and employ about 1.8 million people. Many have taken steps to reduce their emissions and invest in clean energy; some participants, such as Adobe and Ikea, have even committed to running 100 percent on renewable energy.

About 100 investors including Teachers Retirement System and Trillium Asset Management have also signed. The participating investors have a combined $2.18 trillion in assets under management.

"With tens of billions of dollars of U.S. renewable energy investment in the works this year alone, and far more globally, the question for American political leadership is whether they want to harness this momentum and potential for economic growth," Jonas Kron, senior vice president at Trillium Asset Management, said in a statement.

Many groups have already urged the Trump administration to take action on climate change and support renewable energy, including scientists, United Nations leaders, heads of state such as Canada's Justin Trudeau and Germany's Angela Merkel and higher education leaders. It's unclear if Trump, who campaigned on his business experience, will be more responsive to this direct appeal by the business and investment community.

Trump and many of his top cabinet picks have questioned the scientific consensus that the climate is changing and humans are largely to blame. Trump has also threatened to "cancel" the Paris agreement, rollback domestic climate policies and encourage more fossil fuel development.

While no major oil, gas and coal companies have signed the letter—which includes a pledge by the participants to do their part to respond to the climate crisis—there are several participants from the energy industry, including the California utility Pacific Gas and Electric.

"California has ambitious, clearly defined climate goals and is committed to acting as a global leader on this important issue," Melissa Lavinson, PG&E's vice president of federal affairs and policy and chief sustainability officer, said in a statement. "We support the state's vision for a clean energy future and agree that we need to take action today to meet the challenge."

Also signing on is Tesla Motors, which specializes in electric cars and home battery storage, and whose co-founder Elon Musk is a strategic adviser to Trump.

"Pursuing a low-carbon economy absolutely is good for environment," Ron Cotterman, vice president of sustainability at the packaging company Sealed Air, told InsideClimate News. "But the fact that we've figured out how to also make it good for business is the message we want to send."