When Biden arrives at COP26, he’ll face world leaders who are still reeling from Donald Trump’s fossil fuel advocacy and callous withdrawal from the Paris Agreement. The Trump era left many in the global community wondering whether the United States could ever again be considered a trusted partner on climate change. But this goes far beyond simply making up ground lost under Trump; Joe Biden’s presidential legacy at home and abroad will be defined by his action on climate. The Build Back Better framework released yesterday offers Biden the opportunity to pass the most significant climate legislation in U.S. history. 

The good news is that the opportunity for a safer, more livable future is right in front of us. President Biden ran and won on popular commitments to fight climate change while delivering jobs and justice. Whether he can make good on those commitments, however, hinges on Congress passing bold climate policy through reconciliation. 

In April, President Biden pledged to the global community that America would cut greenhouse gas emissions more than half from 2005 levels over the next decade. That’s a goal he can’t reach unless Congress passes the Build Back Better Act; executive actions alone won’t even come close. An analysis from Senate Majority Leader Chuck Schumer’s office found that passing the $3.5 trillion package would reduce U.S. emissions by 45% from 2005 levels by 2030—getting us well on our way to fulfilling President Biden’s 50-52% target. But we’ll only succeed in hitting that target if President Biden and Congressional leadership deliver the BBBA framework with the strong investments needed to meaningfully reduce domestic greenhouse gas pollution, transition our power sector to clean electricity, create millions of new good-paying green jobs, and cement American industry as a global leader in the clean energy economy.

Despite being the world’s largest historic emitter of greenhouse gasses, the United States has never passed comprehensive climate legislation. In 1997, Congress prevented America from ratifying the Kyoto Protocols. In 2010, the Waxman-Markey cap-and-trade bill stalled out in the Senate. And in the next few weeks, Congress will determine whether Biden can turn the tide of decades of inaction to deliver meaningful climate progress.

Democratic leaders have precious little time to act—they must stand firm against the tidal wave of fossil fuel industry lobbying that is attempting to chip away at the Build Back Better Act and they must reject bad faith efforts to delay the reconciliation package in favor of passing a bipartisan infrastructure bill first. The bipartisan infrastructure bill is not a climate bill. It makes no meaningful reductions in greenhouse gas pollution and shortchanges other core Biden climate and environmental justice priorities. When President Biden faces world leaders next week, they won’t ask how many roads and bridges he built with Republican votes, they will want to know when he is going to deliver on the nation’s climate commitments.

As President Biden put it at his climate summit in April, “the commitments we’ve made must become real. Commitment without us doing it—it’s just a lot of hot air.” What Congress does next will determine whether Biden’s climate commitments can become reality, and whether the president will have the credibility to help shape the global response to this crisis. The climate crisis is the existential threat of our time. Either the United States will rise to the challenge under the Biden administration and become a leader in a just, global clean energy economy or we will fail to meet this challenge. Anything else is just hot air.