Editor’s Note: Adam H. Sobel, a professor at Columbia University’s Lamont-Doherty Earth Observatory and Fu Foundation School of Engineering and Applied Science, is an atmospheric scientist who studies extreme events and the risks they pose to human society. Sobel is the host of the podcast “Deep Convection” and the author of “Storm Surge,” a book about Superstorm Sandy. Follow him on Twitter: @profadamsobel. The opinions expressed in this commentary are his own. View more opinion on CNN.

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How important is the climate bill – named, for Joe Manchin-related reasons, the “Inflation Reduction Act” — that just passed the US Congress? Huge.

To get the disclaimers out of the way: it doesn’t, by any means, solve the whole climate problem. We still need to do plenty more to get to zero carbon emissions. And we’re still in for more warming regardless. The heat waves, wildfires, floods and the rest of what we’re starting to see as routine will still get worse for decades more, at least. The bill also has some negatives from a climate perspective, like its new offshore oil leases, presumably added to appease Sen. Manchin, whose vote was crucial to the legislation’s passage.

But still: HUGE!

Consider the history here. For almost the entire 30-year history of international climate negotiations, the US has been more of a problem for the rest of the world than the leader we should have been.

Congress couldn’t find its way to ratify the Kyoto Protocol or any other agreement that mandated actual emissions reductions. The Waxman-Markey bill, the last major climate legislation to come before Congress during a time when Democrats controlled both chambers of Congress and the White House, passed in the House and failed in the Senate in 2010, in the face of a challenging economic climate, intense fossil fuel industry lobbying and GOP opposition (sound familiar?).

Then, in 2015, when Obama reversed the trend and got the Paris Agreement through, it specified only voluntary contributions from participating nations, because that’s the only way he could skip Congressional approval, which would surely have killed it too. (Then-President Donald Trump’s statements of intent to pull us out of the agreement are hard to see as anything but climate- and treaty-hating spite, since one could in fact abide by the agreement while doing nothing to reduce emissions.)

It has always seemed possible, even likely – depending where one falls on the optimism/pessimism spectrum – that some nations would fail to meet their Paris commitments, or simply decide to reduce them by insignificant levels. The US has looked like one of the most likely candidates for such failure, given our dysfunctional political system and the deep allegiance of the Republican Party to the fossil fuel industry.

Then, starting in early 2021, it seemed like maybe we’d actually live up to the Paris Agreement after all… then, not. The last year and a half have been a painful roller-coaster ride for those of us who care about the future of human beings and other species on planet earth, and who accept the global scientific consensus about how climate change threatens us.

When the Democrats narrowly took both the Presidency and both houses of Congress in 2021, there was a period of hope that the “Build Back Better” bill might pass, representing a major triumph for the climate movement as well as addressing many other social justice goals. But after a long period of inscrutable dithering, Manchin pulled the rug out from under BBB, and seemingly any hope for meaningful climate legislation.

Why did Manchin finally change his mind and decide to support the Inflation Reduction Act? I don’t know, and I don’t care. The IRA may have lost much of the non-climate content of BBB, but it has most of the climate stuff. It is expected to deliver somewhere in the vicinity of a 40% reduction in the nation’s carbon emissions by 2030, compared to 2005 levels, most of the way towards President Biden’s pledge of 50-52% over the same time period.

This is the real thing.

There has never – never – been climate legislation anywhere near this substantial passed in the United States. Not only do these emissions reductions truly matter on their own, but they show that it’s politically possible – that enough people care about the climate problem that it can be addressed by our political system. And they allow us to look other nations in the eye as we ask them to do their parts too.

With regards to politics, the IRA does its work to fight climate change mostly through investment, rather than regulation or taxes. It gives people and businesses money – some directly and some through tax breaks – to spend on electric cars, heat pumps, wind and solar electricity generation, and many other emissions-reducing measures.

It will stimulate growth and good jobs in the private sector. They will make further emissions reductions possible, as technologies improve more quickly than they otherwise would. Maybe the industries that grow out of this will even gain political power comparable to that of the fossil fuel industry, creating a countervailing force. (One can dream.)

The US is currently responsible for about 11% of global emissions, according to a report by research and consulting firm Rhodium Group. Cutting 40% of that by 2030 is a meaningful contribution on its own. But to get to zero emissions globally, we will need the rest of the world, including countries like China and India, to agree to cuts as well. Until now, our credibility in climate negotiations has been weak, due to our own poor record (including our status as the nation responsible for the most emissions historically, when we add up all past years rather than just considering the most recent ones).

The IRA transforms the US from ineffective negotiators to leaders by example. And the technological development the IRA’s investments will induce will make the necessary global emissions cuts easier, in the same way that past investments in solar panels, for example, have driven down the costs of the necessary technologies and increased their effectiveness.

This investment approach reflects a change in thinking in recent years among some climate policy experts – not least those in the Biden administration – away from carbon taxes or cap-and-trade systems like the one that failed to become law in Waxman-Markey. This rethinking places increased emphasis on overcoming real-life political constraints, including the failure of Waxman-Markey itself and the increasing partisan polarization since then, with a decreased emphasis on doing what economists’ models (which don’t generally account for politics) say is optimal. The passage of the IRA seems to have proven this right.

There has been a huge focus on Manchin, for obvious reasons, but this should be said: every Republican who voted against the IRA – which is all of them – should be profoundly ashamed of themselves.

Their repeated claims about taxes and inflation can’t disguise where they really stand: somewhere between flat-out denial that the climate problem exists and grudging acknowledgment of it, coupled with delay tactics and a total lack of interest in doing anything about it. It may have moved a bit away from the denial in recent years, but the practical result is still inaction. Manchin wouldn’t have mattered nearly so much if any GOP senator had shown any inclination whatsoever to be constructively engaged.

No, the real change is that the Democratic Party, which has for many years been either unwilling or unable to do much about climate change, has finally placed it at the top of its agenda and mustered the will to pass the historic legislation against difficult odds.

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    This cannot be taken for granted for one microsecond. In my view, the youth climate movement – along with its older allies – should get the lion’s share of the credit for turning up the pressure and bringing the issue to the forefront of people’s minds. (And, perhaps, let’s acknowledge the contributions from my colleagues, the hard-working scientists, who have spent decades doing research, writing papers, and compiling them into IPCC reports and National Climate Assessments to spell out the ever-grimmer facts.)

    But in a time when the twin, slow-moving catastrophes that are US politics and the global climate crisis make it so painful for so many of us to read the news every day, it’s important to take a moment and celebrate when something good happens. This is such a something. It really is. Well done, President Biden and team – even Joe Manchin, who was for many months reluctant to support such a bill – and everyone else who pushed it to this point