President Trump has now fulfilled his disastrous promise to pull the United States out of the Paris Climate Agreement. The agreement represents decades of work by both Democratic and Republican administrations to achieve a common goal: bringing every country of the world together to tackle the climate crisis, the existential threat of our time.

President Trump surprised no one with his decision to withdraw from the agreement. It is yet another reckless choice in line with his steps to rollback our bedrock environmental laws, which have cleaned up our water and our air for decades. But that doesn’t minimize the gravity of his latest move. Trump is not only ceding American leadership at a critical juncture in the fight against climate change, he’s also giving away American jobs in the clean energy economy of the future – walking away from the greatest economic opportunity of our time.

The science is clear: the costs of climate change are even greater than we thought. In fact, a report released last year by Trump’s own government found that by the end of the century climate change will cost the American economy hundreds of billions of dollars and thousands of lives every year. We are already seeing the cost of inaction here at home – bigger wildfires in California, record flooding in the Midwest and stronger hurricanes from Houston to New Orleans. And the global costs are even greater: climate change is making already unstable governments even less so, fueling international conflicts, and creating climate refugees around the world. It’s also spreading diseases into new parts of the world, costing more lives. With each passing year, the climate crisis wreaks greater havoc.

But instead of acting to protect American lives and creating good paying jobs, we have let Big Oil set our climate policy in Washington. These companies spent three decades deceiving the public about the climate crisis, spreading lies and misinformation through their lobbyists. With Donald Trump in the White House, they now have a climate denier in chief.

President Trump continues to peddle lies about the climate crisis, while he lets big polluters go back to poisoning our air and water. He falsely claims that complying with the Paris Agreement would cost Americans “billions of dollars and put millions of jobs at risk for no meaningful reduction of emissions.” This couldn’t be further from the truth. The World Bank estimates that the Paris Agreement created a $23tn investment opportunity over the next decade in just the top 20 developing countries. As these countries move toward 100% clean energy, and other countries of the world join them, markets for America’s clean energy innovation will only expand.

My Green Manufacturing Plan will jumpstart clean energy development right here in the United States by investing $2tn to grow clean energy at home and abroad, while creating millions of new, good paying, union jobs. And my Green Marshall Plan would directly assist countries abroad to buy American-made clean energy products, further expanding markets for green manufacturing.

The next president must rejoin the Paris Agreement, but that alone is not enough. Instead, she must show the world that the United States is ready to once again lead on the international stage. The first step is to submit a new US commitment under Paris raising our previous target to achieve rapid emission reductions. I have a plan for that. Next, we must encourage other nations like China and India to step up in this fight alongside us. And climate change must be an organizing principle in American diplomacy. That means whether it’s negotiating new trade agreements or addressing security threats, my administration will consider the impacts of climate change as we make foreign policy decisions.

The world is facing one of the biggest threats we have ever encountered. But Americans do not walk away from a fight. We lead. In November 2020, it won’t just be Donald Trump on the ballot but also the chance to renew America’s climate leadership for a safer, cleaner, more secure and more prosperous future.