Actor Leonardo DiCaprio joined the growing movement to force companies to divest from fossil fuels, appearing at a press conference for the "divest/invest" initiative.

"Divest/invest" aims to move investments out of fossil fuels and into cleaner energy sources.

DiCaprio pledged to divest his own investments from fossil fuels, as well as those assets managed by the Leonardo DiCaprio Foundation.

"Now is the time to divest and invest to let our world leaders know that we, as individuals and institutions, are taking action to address climate change, and we expect them to do their part this December in Paris at the U.N. climate talks,” DiCaprio said in a statement.

DiCaprio joins fellow actor and environmentalist Mark Ruffalo in his divestment pledge.

The Leonardo DiCaprio Foundation has awarded $30 million in grants since 1998, according to its website, and says it raised another $40 million in July. The foundation is part of the California Community Foundation, which puts it in a category of tax-exempt charities that don’t file publicly available tax forms, which makes it difficult to determine the magnitude of its divestment commitment.

The overall divestment movement, which started on university campuses and religious institutions around the world but is now spreading far beyond that, has hit the $2.6 trillion mark, according to an analysis released at the event in New York on Tuesday.

The report, from Arabella Advisors, found that to date, 436 institutions and 2,040 individuals across 43 countries, together representing $2.6 trillion in assets, have committed to divest from fossil fuel companies.

This $2.6 trillion figure does not mean that money is being taken out of fossil fuels themselves. Instead, it is a show of power: the total amount of money under management by organizations committed to divestment. Most institutions that have made commitments have about between 3% and 8% of their overall assets invested in fossil fuels.

For example, one of the largest Norwegian pension funds, KLP, which has $60 billion under management, previously said it would sell "coal-related shares and bonds worth approximately $60 million," in addition to spending $60 million to invest in new renewable energy production in emerging markets.

Some of the most prominent institutions that have agreed to divest from coal, oil and other fuels that emit planet-warming greenhouse gas emissions include the Rockefeller Foundation, Guardian Media Group, University of California system, California Pension Funds and the Norwegian Sovereign Wealth Fund.

“If you had pulled out of fossil fuels in the last 5 yrs, you have outperformed the market,” @TomVanDyck from RBC Wealth Management #divest — Jamie Henn (@Agent350) September 22, 2015

Even with this caveat, the growth rate of the divestment movement is staggering.

"Clearly our movement is growing faster than anyone expected, and clearly the world is moving away from fossil fuels," said Mary Boeve, the executive director of climate advocacy organization 350.org.

Last year, Arabella Advisors calculated that the total amount of funds committed to divestment totaled a comparatively paltry $50 billion in assets, with 181 institutions and under 1,000 individuals taking part in the movement.

This means that since then, there has been a 50-fold increase in the assets of those committed to divestment.

"In 2014, foundations, universities, faith-based organizations, NGOs, and other mission-driven organizations led the movement," the report stated. "Today, large pension funds and private-sector actors such as insurance companies hold over 95% of the total combined assets of those committed to divest."

One of the reasons that divestment is spreading in the financial industry is a growing recognition that investments in fossil fuels, particularly coal and unconventional oil and gas resources, may constitute a financial risk for so-called stranded assets, given the push for government regulation of greenhouse gases and the increasing speed and impacts from global warming already evident around the world.

Institutions committing to divest from fossil fuels, broken down by sector.

Recent reports from the Carbon Tracker Initiative, International Energy Agency, HSBC and Citigroup have each warned of the financial consequences of holding large portfolios of fossil fuels.

"The leaders of several of the largest institutions to divest in the past year have cited climate risk to investment portfolios as a key factor in their decisions," the report found.

The divestment movement is aimed in part at influencing global climate talks, which will come to a head in Paris in December, when governments will try to agree on a new global climate treaty that would apply to all countries after the year 2020.

"... As world leaders gather in Paris at the end of the year, we need governments to divest also," Boeve said.

In addition to growing in dollar figures, the divestment movement has also become more diverse geographically.

Last year, 78% of divesting institutions were based in the U.S., but that is now down to 57%.