Fifty-three years later, Congress is on the verge of finally answering what Mr. Moynihan called “the carbon dioxide problem.” On Sunday, Senate Democrats backed a $369 billion bill designed to shift the country away from fossil fuels and toward solar, wind and other renewable energy sources. If the House passes the legislation later this week as expected, it would mark the nation’s first major climate law as scientists warn that nations have only a few years left to make deep enough carbon cuts to avoid planetary destruction. Once in effect, the new law is projected to help reduce the nation’s greenhouse pollution by about 40 percent below 2005 levels by the end of this decade. That’s not enough to avoid the worst effects of a warming planet, but it would be a pretty big advance and the most climate action the United States has ever taken. “Finally, now we’ve crossed a major threshold,” said former Vice President Al Gore, who as a lawmaker held the first congressional hearings on the issue in 1982 and shared the 2007 Nobel Peace Prize with climate scientists for their joint efforts to spread awareness. about climate change. “I didn’t imagine for a moment that it would take this long.” In interviews, Mr. Gore and others pointed to several reasons why a climate bill is finally set to become law — passing the Senate by a slim 51-50 majority, with Vice President Kamala Harris tied. All said the unmistakable evidence that climate change has already arrived — in the form of terrifyingly extreme fires, droughts, storms and floods hitting every corner of the United States — helped build political support. Increasingly, the vast amount of real-time data has overwhelmed the well-funded decades-long strategy of oil, gas and coal companies to cast doubt on the seriousness of climate change. But they also signaled a shift in strategy, swapping what experts see as the most effective way to cut carbon dioxide emissions, a tax on pollution, with the less effective but more politically palatable approach of monetary incentives for industries and consumers to switch in pure energy. In effect, lawmakers replaced sticks with carrots. William Nordhaus, who first conceived of the carbon tax as a young economist at Yale University in the 1970s, wrote in an email: “Carbon taxes have proven to be a toxic mix of politics, although the toxicity varies from country to country. country. Subsidies, on the contrary, are culinary for the elected.” Mr. Biden has promised that the United States will stop adding carbon dioxide to the atmosphere by 2050. All major economies must follow suit to limit the rise in average global temperatures to 1.5 degrees Celsius above pre-industrial levels, scientists say. This is the threshold beyond which the likelihood of catastrophic droughts, floods, fires and heat waves increases significantly. The planet has already warmed by an average of about 1.1 degrees Celsius. Without putting a price on carbon pollution, it will be difficult for the United States to reach its net zero goal by 2050, experts say.

The Biden administration’s environmental agenda

President Biden is pushing for tougher regulations, but faces a narrow path to meeting his goals to combat global warming.

“The carbon tax has been the dream of people who want to be good stewards of the planet for decades,” said Douglas Brinkley, presidential historian. “But instead, the reality of American politics is that you give a chunk of cash to stimulate new technology. It won’t be enough to reach the 2050 goal. But it’s still the biggest thing the US has ever done on climate change.”

False starts

A few years after Mr. Moynihan’s memo to the Nixon White House, Mr. Nordhaus proposed an elegant solution: governments should impose a tax, fee or some other price on carbon pollution. By 1988, climate change had begun to make headlines. James E. Hansen of the National Aeronautics and Space Administration told a Senate committee that human-caused global warming had already begun. The following year, Dr. Hansen testified before a Senate subcommittee chaired by Mr. Gore, who felt momentum was building to pass legislation to stop further global warming. As vice president in 1993, Mr. Gore helped push a measure that would have accomplished the same thing as the carbon tax. But after the bill passed the House, Republicans attacked it as an “energy tax” and the Senate never took it up. The following year, Republicans promised to cut taxes and reform the government and won control of both houses of Congress for the first time since 1952. “It was kind of crazy, because Clinton and Gore got the House to vote on it, even though it was a suicide,” said Paul Bledsoe, who was a Senate staffer at the time and later worked in the Clinton administration. “This has delayed climate policy for more than a decade. It was politically disastrous.” Climate policy lay dormant in Washington until 2009, when President Barack Obama tried again with a cap-and-trade bill. While not a direct carbon tax, it would have set a shrinking limit on the amount of carbon dioxide pollution that could be emitted each year and forced industries to pay for pollution permits. History repeated itself. The measure passed the House, but within days Republicans labeled it an “energy tax.” Although Democrats controlled both houses of Congress, the Senate never took up the bill, unable to muster enough votes in their own party to pass it in the face of Republican opposition. Sen. Sheldon Whitehouse, D-Rhode Island, recalled Sen. Harry Reid of Nevada, then the majority leader, telling him in July 2010 that there would be no further efforts to move climate legislation. Democrats had fought hard to pass the Affordable Care Act “and they didn’t want another conflict,” Mr. Whitehouse said Mr. Reid told him. The aftermath “was a long, bleak period”, Mr Whitehouse said. In 2012, he began making almost weekly speeches from the Senate floor, continuing to this day, warning of the dangers of global warming. “I just decided, look, we’re not going to stop talking about climate change in this place,” he said. In Mr. Obama’s second term, after Democrats had lost control of the House, the president enacted a series of regulations to reduce carbon dioxide pollution from cars and power plants. Some Republicans still expressed doubt that human activity was causing climate change or even that the planet was warming at all. In February 2015, Senator James Inhofe, R-Oklahoma, famously held up a fat snowball on the Senate floor as proof that global warming was a hoax. Mr. Obama’s successor, President Donald J. Trump backed down and weakened emissions standards, demonstrating the fragility of executive action.

Change of policy and another chance

As efforts on Capitol Hill to address the climate crisis faltered and stalled, policy was beginning to shift, according to activists and lawmakers. Evidence of climate change has become increasingly visible in congressional districts, with powerful storms causing death and destruction, severe droughts threatening water supplies and dangerous heat waves taxing power grids. A major 2017 scientific report, the National Climate Assessment, detailed the economic costs of climate change, from record wildfires in California, crop failures in the Midwest, and crumbling infrastructure in the South. In the past five years, the United States has experienced 89 weather and climate disasters with more than $1 billion in damage each, costing the country a total of $788 billion and 4,557 lives, according to the National Oceanic and Atmospheric Administration. Last summer was the hottest on record in the contiguous United States, but it’s on pace to surpass this summer. By and large, Republicans stopped denying that the planet is warming and instead opposed climate action on economic grounds. At the same time, the sunk costs of natural gas and renewables have weakened the coal industry. Environmentalists form alliances with groups they have allied with in the past, such as labor unions and farmers. They began to talk about climate change not only as a threat to polar bears and coastlines, but also as an opportunity for the United States to develop a new economy without fossil fuels. “The movement had to mature,” said Sen. Brian Schatz, D-Hawaii, who fought back tears immediately after Sunday’s vote. “There is a lot to destroy, but this was no way to build political momentum. We started to try to answer the question, ‘What’s in it for me if we take climate action’ as a farmer, a surfer, a union worker.” President Biden took up this slogan, equating climate action with jobs when he won the White House in 2020, helped in part by a record turnout of young climate-conscious voters. But Joe Manchin III, the Democrat from coal-rich West Virginia and a crucial vote in an evenly divided Senate, would define the limits of what was possible. As Democrats tried to push through a broad spending bill that would include climate provisions, . Senators took one last stab at putting a price on carbon. They tried to include a measure that would have rewarded utilities that replaced fossil fuels with clean energy sources and penalized those that didn’t. That provision would have allowed the United States to meet Mr. Biden’s long-term climate goals and quickly transform the…