James Hansen's Hot June Day Before the Senate in 1988

The summer of 1988 was brutal. A drought had settled over the Midwest and the Plains, barges were stranded on a shrunken Mississippi River, and crops were burning up in the fields. In Washington, on Thursday, June 23, the temperature climbed into the high nineties. Inside a Senate hearing room, the air conditioning seemed to be struggling, and the television lights made it worse. Into that heat walked James Hansen, a soft-spoken scientist who directed NASA's Goddard Institute for Space Studies in New York. He was a modeler of climates, including the scorching one on Venus, and he was not a natural performer. He testified to the Senate Committee on Energy and Natural Resources that the Earth was warmer than at any time in the history of instrumental measurements, that he was ninety-nine percent confident the warming was not a natural fluctuation, and that the greenhouse effect was already here. Afterward, he told reporters it was time to stop waffling. The next morning, the story was on the front page of The New York Times. Global warming, a subject scientists had discussed for decades, had become a political issue. What Washington did with it is a much longer and sadder story.

In short: James Hansen's 1988 Senate testimony made climate change a national issue overnight. It led quickly to new international institutions and a 1992 treaty, but a long series of bills, from a 1993 energy tax to the 2009 cap-and-trade bill, failed in the Senate before Democrats passed major climate spending in 2022. The lesson is less that Washington ignored the science than that it kept losing votes it needed.

A hearing built for the weather

The hearing did not happen in that heat by chance. Senator Tim Wirth, a Colorado Democrat who had been trying for years to get attention for the issue, worked with committee staff to schedule it, and he later said they had looked up which day of the summer was historically the hottest in Washington. He also said, in interviews years later, that staff had opened the windows of the hearing room the night before so the air conditioning would struggle. However much of that story is embellished in the retelling, it captures something true. Wirth understood that facts need a stage.

The committee was chaired by Senator Bennett Johnston, a Louisiana Democrat from an oil-producing state. Other scientists testified that day as well. But Hansen's words, plain and unhedged, were what carried. Scientists had been describing the greenhouse effect for more than a century, from Eunice Foote and John Tyndall in the 1850s to Svante Arrhenius in the 1890s, who estimated how much a doubling of carbon dioxide would warm the planet. What changed in 1988 was a credible government scientist saying that the warming was no longer a projection. It was underway.

The season kept making the argument after the hearing ended. Later that summer, wildfires swept through Yellowstone National Park, and television carried images of the country's oldest national park in flames for weeks. Farmers in the Corn Belt watched yields collapse, and Congress passed drought relief for them. None of those events proved anything about climate change on its own; a single hot summer is weather, and scientists said so at the time. Hansen himself was careful to say that no one drought could be blamed on the greenhouse effect, only that warming made such summers more likely. But public attention does not follow the rules of statistics. A country sweating through a terrible summer was ready to listen to a scientist who said the heat was a sign of things to come, and the politicians in the room knew it.

That is a lesson with two edges. Weather can open a door for climate policy, but it can also close one: a cool, rainy summer makes the issue easier to ignore. Building policy on a stretch of bad weather is building on sand. The durable case rests on the long record, decades of measurements that do not depend on what the thermometer says this afternoon.

What the science said then

Hansen's testimony drew some criticism from fellow scientists, who thought he was more certain than the evidence warranted. His argument rested on the temperature record, which showed the 1980s as unusually warm, and on climate models that projected continued warming as carbon dioxide rose. His team's projections, published that year, laid out several scenarios depending on how much emissions grew.

In hindsight, the broad picture he described held up: the warming continued, and each decade since the 1980s has been warmer than the one before. Climate science has become far more detailed since 1988, but the core claim that drew skepticism at the time, that humans were warming the planet and the warming was detectable, is now the consensus of the major scientific academies and of the Intergovernmental Panel on Climate Change, which, as it happens, was founded that same year.

A fast start

The first response was encouraging. In 1988, the World Meteorological Organization and the United Nations Environment Programme established the IPCC to assess climate science for governments. On the campaign trail that year, Vice President George H. W. Bush promised to meet the greenhouse effect with the "White House effect," a line meant to show he took the issue seriously.

Bush's presidency was more complicated. In 1989, Hansen's own congressional testimony was edited by the White House budget office to soften his conclusions, and when he disclosed it, the episode became a scandal. But the Bush administration also took part in negotiations that produced the United Nations Framework Convention on Climate Change at the Earth Summit in Rio de Janeiro in 1992. The Senate approved the treaty that year with bipartisan support, and it remains the legal foundation for global climate talks, including Paris. Its goals were voluntary, and emissions kept rising. But for a few years, it looked as though Washington might move.

The long string of near misses

Then the votes started going the other way. In 1993, President Bill Clinton proposed a broad tax on energy based on its heat content, called the BTU tax. The House passed it. Senators from energy-producing states, including Democrats, balked, and the tax was dropped and replaced with a small increase in the gasoline tax. Several House Democrats who had voted for the BTU tax lost their seats the next year, and the lesson that climate votes are dangerous settled into the party's memory.

In 1997, before the Kyoto Protocol was even negotiated, the Senate voted 95 to 0 for a resolution warning against any treaty that did not include developing nations. Kyoto was never submitted for ratification. In the 2000s, Senators John McCain and Joe Lieberman, a Republican and a Democrat, introduced bipartisan cap-and-trade bills that got votes but fell short of passage.

The closest call came in 2009. With large Democratic majorities, the House passed the American Clean Energy and Security Act, known as Waxman-Markey, by a vote of 219 to 212 in June. It would have set a declining cap on greenhouse gas emissions. The Senate never took it up. Democrats from coal and oil states were reluctant, Republican support evaporated, and the financial crisis and the fight over health care consumed the calendar. When the Senate's leaders shelved the effort in 2010, the window closed for more than a decade.

Why the votes kept failing

It would be easy to say that Washington ignored the science. That would be wrong. The record shows hearings, treaties and repeated bills. The problem was in the incentives.

Climate policy asks people to pay costs now for benefits that arrive later and spread across the whole world. The costs fall heavily on specific regions, such as coal country and oil states, whose senators have equal power under the Senate's rules. The fossil fuel industry spent heavily on lobbying and, for years, funded groups that cast doubt on the science. And voters who cared about the issue rarely ranked it first, while voters in energy regions often did.

Progressives also made mistakes. Cap-and-trade was an elegant economists' design that most voters never understood and opponents easily branded as a hidden energy tax. Environmental groups sometimes treated people in fossil fuel communities as obstacles rather than constituents. And climate policy was often presented as sacrifice rather than as jobs, lower bills and cleaner air.

The other side's best case was and is a serious one: that unilateral American cuts would make little difference if China and India kept raising emissions, and that higher energy costs fall hardest on the working poor. Those concerns are why later climate policy changed shape.

Meanwhile, in the states

While the Senate stalled, states did not wait. Their record is one of the more hopeful parts of the story, and it crosses party lines more than the national debate suggests.

Iowa, a farm state, passed one of the first laws requiring utilities to buy power from renewable sources in 1983, years before Hansen's testimony. Over the following decades, most states adopted some version of a renewable portfolio standard, a requirement that a growing share of electricity come from clean sources. Texas, under Governor George W. Bush, adopted one in 1999, and the state went on to build more wind power than any other. Those wind farms rose across the same plains that had baked in the 1988 drought, and they now pay lease money to ranchers and farmers in counties that vote heavily Republican.

In the Northeast, a group of states launched the Regional Greenhouse Gas Initiative in 2009, the first mandatory cap-and-trade program for power plants in the country, with Republican and Democratic governors among its founders. California passed its Global Warming Solutions Act in 2006, signed by Governor Arnold Schwarzenegger, a Republican, and later built an economy-wide cap-and-trade program. Many cities and states set their own clean energy targets after the federal government pulled back.

The states could not solve the problem alone. Their power is limited, and pollution crosses borders. But they proved two things Washington had doubted. Clean energy policy could survive elections, and it could grow an economy rather than wreck one. Those lessons, learned in statehouses, shaped the incentive-based design of the 2022 federal law.

It also matters who built that record. Much of the work was done by people far from the Senate hearing room: public utility commissioners, rural electric cooperatives, farmers who leased land for turbines, and local organizers who showed up at hearings on power plants. When Washington is stuck, the next move often comes from the places closest to people.

What finally passed, and what was undone

The bill that broke the logjam was built differently. The Inflation Reduction Act of 2022 used tax credits and investments instead of caps or taxes: incentives for wind, solar, batteries, electric vehicles, heat pumps, domestic manufacturing and clean energy in communities that had lost coal plants. The Congressional Budget Office estimated its energy and climate provisions at roughly $370 billion over ten years. It passed the Senate with no Republican votes, 51 to 50, with Vice President Kamala Harris breaking the tie. Much of the new investment it attracted landed in Republican-held districts.

In 2025, the Republican Congress passed and President Trump signed a tax and spending law that rolled back or phased out many of those credits, especially for wind, solar and electric vehicles, while keeping some for nuclear power, geothermal and carbon capture. Some Republican lawmakers whose districts had new factories pushed to keep parts of the program, and some of those protections survived. The fight over what remains is one that the new Democratic majorities elected in November 2026 will face once they are seated in January 2027.

What Hansen did next

Hansen did not stay a quiet government scientist. In the 2000s, he publicly accused political appointees at NASA of trying to limit his speaking about climate. He began speaking out as an advocate, was arrested at protests against mountaintop coal mining and the Keystone XL pipeline, and retired from NASA in 2013 to devote himself to research and advocacy. Some colleagues objected that advocacy compromised his science; others thought a scientist who believes the evidence demands action has an obligation to say so. Either way, he remains the man who stood up in a hot room in 1988 and said the thing out loud.

His story leaves the rest of us with a question about how democracies handle slow, enormous problems. The science was clear enough in 1988 to act on. The politics took thirty-four years to produce a major law, and less than three to undo much of it.

What you can do

• Know what your own members did. Climate votes are on the record. The Congress votes and bills page shows how your representatives voted, and our page on Democrats in Congress follows what the new majority is planning.
• Make the call that 1993 lacked. Members from energy states need to hear from constituents who want clean energy jobs as much as from those who fear the cost. Find yours through the representatives lookup and tell them which kind of constituent you are.
• Watch the temperature record he warned about. Our climate data page shows the global temperature record and clean power state by state, so you can see how your state compares.
• Keep up with the policy. The climate policy page tracks the credits that survived, the ones that did not, and what Congress may try next.