BOSTON -- Environmental activists concerned about global warming chained themselves to the front entrance of the Bank of Boston building on Boylston Street in Boston early Tuesday.

They said they were protesting the bank's funding of coal and energy companies which they said are among the worst contributors to climate change.

The April Fool's prank was part of the Fossil Fools Day of Action, which took place in coordination with 100 other rallies, protests and other acts of civil disobedience around the country, the group said.

They said the protests are designed to "challenge and disrupt the fossil fuels industry," which some scientists say is primarily responsible for global warming.

The protesters claim Bank of America has loaned more than $144 billion to companies such as Massey Energy, Arch Coal and Peabody Energy, which engage in strip mining and mountaintop removal coal mining.

"Without the financial support of large banks like Bank of America, the fossil fuels industry could not continue destroying the earth and our communities," protester Elise Ansel said.

The activists said coal-burning power plants are responsible for 40 percent of U.S. greenhouse gases that cause global warming.

"It’s not just an environmental issue. The people who are most affected by the coal industry are already disadvantaged by this economic system," said Laila Murad of Brighton. "Coal plants are often built in low-income neighborhoods and communities of color, and the coal is most often mined in poor areas and on indigenous land. Coal mining is just another chapter in a long and bloody story of colonialism and injustice."

The Fossil Fools Day of Action was called for by Rising Tide North America, Rainforest Action Network, and the Energy Action Coalition.