The logo for ExxonMobil appears above a trading post on the floor of the New York Stock Exchange, April 23, 2018. Credit: Richard Drew | AP

ExxonMobil will give $1 million over two years to a group promoting a plan that would tax the carbon content of fuels including the oil giant’s own products and return the proceeds of the tax to Americans.

ExxonMobil said the $1 million would go to Americans for Carbon Dividends, a 501(c)(4) educational and advocacy organization created to support a carbon tax-and-dividend plan put forward by a group, including former treasury secretary James A. Baker III and former secretary of state George P. Shultz.

The tax would be $40 per ton of carbon dioxide, equal to about a 36 cents a gallon of gasoline tax. It would also raise costs for natural gas and coal.

“A company getting behind its product being taxed is a very rare thing,” said Lawrence Summers, a Harvard University economics professor and former treasury secretary. “This reflects a new and important awareness that we have to do big things about climate,” he said and praised “the impressive bipartisan coalition behind the carbon dividend approach.”

ExxonMobil has long supported a carbon tax. In 2009, the company’s then-chief executive Rex Tillerson backed a $20-a-ton carbon tax at a speech in Washington. But Tillerson never pressed lawmakers on the issue. Other major oil companies, including BP and Royal Dutch Shell, have supported carbon taxes.

Recently, ExxonMobil joined the Climate Leadership Council, which was created to develop the Baker-Shultz plan, under which a carbon tax would be established at $40 a ton and increase steadily over time. The revenue would be returned to Americans on an equal and monthly basis via dividend checks, direct deposits or contributions to their individual retirement accounts. There would be border adjustments to ensure fair trade, and it would be accompanied by “regulatory simplification.”

Mark McKinnon, a senior adviser to Americans for Carbon Dividends, said ExxonMobil’s contribution was “a watershed moment,” and he expected that “with their participation, you’ll see a lot of other corporations who have been closely watching this process decide the time is right for them to lend their support, as well.” McKinnon is a veteran political consultant who worked for President George W. Bush.

The size of the donation isn’t large by ExxonMobil standards. The company spends that much on its capital investment program every 20 minutes or so. And a carbon tax faces widespread opposition in Congress.

Nonetheless, ExxonMobil is the most powerful member of the American Petroleum Institute, which has opposed the carbon tax.

“Look at how we got where we are today as the world leaders in carbon reduction. It wasn’t through government mandate, it wasn’t through a carbon tax, it wasn’t through any directive,” former API president Jack Gerard said in 2015. “It was primarily driven by market forces within a context of all-of-the-above [energy].”

In the past, ExxonMobil has also been criticized for its support of other organizations that cast doubt on climate science, most notably the Competitive Enterprise Institute.

Former senator John Breaux, who has been lobbying for the tax-and-dividend plan, said that “when you have members making individual decisions, sometimes that also influences the association.”

Breaux said that while there has been little public support among lawmakers for the tax-and-dividend plan, in private, there is bipartisan support. He said ExxonMobil’s backing was the most important step in building support since President Donald Trump announced the United States would withdraw from the Paris international climate accord.

Other companies supporting the plan include Exelon, BP, First Solar, General Motors, Shell, Total and PepsiCo.

Follow the Bangor Daily News on Facebook for the latest Maine news.