Congress must act if the United States wants to avoid the worst impacts of climate change, say climate activists such as the Environmental Defense Fund. But right now, those activists have basically no realistic hope for any such action.
The make-up of Congress -- the fact that it's Republican-controlled and the GOP is more concerned about the adverse economic impact of trying to mitigate climate change -- would suggest why.
Republicans, who don't have a clear way to block any agreement President Obama signs in international climate talks in Paris, are instead putting up a series of roadblocks and voting to roll back his plans to curb emissions back home.
But there's a longer pattern of Congress opting not to address climate change that give climate activists reason to be pessimistic. Like, really pessimistic. In fact, Congress has never actually passed any substantial legislation out of both chambers to deal with climate change.
Here is a short history -- and we do mean short -- of Congress's attempts to combat climate change.
1990: A cap and trade program for acid rain
As Americans gradually started becoming more aware of climate change in the 1980s and '90s, legislative attention focused on the most sinister of pollutants: acid rain, primarily caused by sulfur dioxide from coal-fired power plants.
The move to cap (put a limit on how much sulfur dioxide plants could emit) and trade (allow companies to buy and sell permits to emit sulfur dioxide) was conceived by a former lawyer in the Reagan White House and championed by President George H.W. Bush, as told in a 2009 article by Richard Conniff in Smithsonian Magazine.
An initially reluctant Democratic Congress came around to the market-based approach, and Congress approved the first cap and trade program in the Clean Air Act of 1990.
Even though the acid rain problem was not a specific response to curb greenhouse gases, Conniff called the program "one of the most spectacular success stories in the history of the green movement," suggesting it was an important blueprint for legislation to help curb global warming in the future.
1992: Agree (but only in principle) to fight global warming
In 1992, President George H.W. Bush returned home from Rio de Janeiro with a signed copy of an international agreement to commit to stabilizing greenhouse gas emissions and mitigating the potential harms from global warming. The agreement was a first step ahead of 1997's international meeting on climate change in Kyoto, Japan.
Bush handed the United Nations Framework Convention on Climate Change over to the Senate, which ratified it without too much trouble.
But the framework wasn't binding, and when it was time to put words to actions by 1997 negotiating the binding Kyoto Protocol, lawmakers back in Washington were reluctant to do so. They argued that an inordinate amount of the burden was placed on developed countries like the United States while developing countries could still pollute at much higher rates.
The Senate passed a resolution expressing its disapproval 95-0, and even though President Bill Clinton returned home with a signed copy of the Kyoto Protocol, he didn't even bother to ask Congress to bring it up for a vote.
2003: Try to expand cap and trade to carbon emissions
More than a decade later, the acid rain cap and trade program had been working well; it was on track to cut sulfur dioxide emissions in half.
But trading for carbon pollution linked to global warming proved to be a different ballgame entirely. The first lawmakers to try to do that were Sens. John McCain (R-Ariz.) and Joe Lieberman (then a Democrat from Connecticut), who introduced a cap and trade bill the same year the Pentagon published a report recommending elevating the debate on climate change from a scientific inquiry into a national security concern.
"Too much attention has been focused on the uncertainties, and not enough on what is known in tackling the problem at hand," McCain said in a statement at the time.
The bill failed in the Senate, with just 43 votes in favor, but climate activists were optimistic that their first shot at finding a legislative solution to curb global warming had some bipartisan support.
Turns out their optimism was misplaced. McCain and Lieberman reintroduced versions of the bill in 2005 and 2007, but each time the proposals got less and less support, until the final one failed to even get out of committee.
2007: The year of talk, but no action
In 2007, a brewing court battle about whether the Environmental Protection Agency had the authority to regulate greenhouse gases without congressional action bubbled up to the Supreme Court. The court decided in Massachusetts v. EPA that, yes, the EPA could tighten regulations on cars and trucks to limit their pollutants that cause global warming.
Philip Wallach, a fellow at Brookings Institution, writes that most climate observers expected Congress to act on the momentum from that Supreme Court decision. And there was some talk of doing just that. That year, the Senate held a rare, hours-long open forum where it seemed like there was bipartisan support for doing something.
From Washington Times coverage of that event:
Sen. Lamar Alexander, Tennessee Republican, said that even his conservative district recognizes “it is now time for Congress to take reasonable steps.”
In the House, then-Speaker Nancy Pelosi (D-Calif.) formed a special committee to hold hearings across the country on climate change. And on the presidential trail in the 2008 general election, both McCain and Obama promised to make climate change legislation a priority in the White House.
But for all that talk, Congress "accomplished precisely nothing," Wallach wrote.
2009: A cap and trade bill passes the House, crashes in the Senate
It wasn't for lack of trying, he said.
When Obama won the White House, climate change activists made a move in the Democratic-controlled Congress to finally pass that carbon cap and trade bill.
The sweeping proposal they came up with would have set a cap on nearly every fossil fuel power plant and manufacturer. It would have affected nearly all Americans in some form or another. The cap would grow tighter every year, making it more expensive to pollute, with the hope that the private sector would find ways to produce cleaner energy.
President Obama praised it as "a bold and necessary step."
And after a messy affair full of wheeling and dealing -- the New York Times reports then-Secretary of State Hillary Clinton and former vice president Al Gore made personal visits to fence-sitting Democrats -- the House passed it by a razor thin margin, 219-212, with 44 Democrats voting against it.
It was the first time a chamber of Congress had approved a bill meant to curb the gases, a victory of sorts.
All that effort was for naught in the Senate, though, where Sens. John Kerry (D-Mass.) and Barbara Boxer (D-Calif.) failed to find a single Republican co-sponsor to bring up their version of cap and trade.
The end (for now)
After the cap and trade bill debacle, Republicans predicted Democrats would pay a heavy price at the polls in midterm elections the next year. And they did: Republicans rather successfully used the cap and trade vote against Democrats -- along with Obamacare, of course, in districts where energy production was big. Democrats lost the House, and there's been no serious movement on legislation to curb greenhouse gas emissions since.