Climate change threatens every corner of our country, every sector of our economy and the health and future of every child. We are already seeing its impacts and we know the poorest and most vulnerable people in the United States and around the world will suffer most of all.

Despite the seriousness of the threat, the world has not always rallied to respond. For years, international negotiations were stymied by deep divisions between developed and developing nations, and by resistance on the part of the Chinese and others to taking responsibility for curbing carbon pollution. While President Obama has made strong progress cutting pollution and deploying more clean energy in the United States, he faces a Republican Party that alternates between denial of the reality of climate change, defeatism about our ability to do anything about it, and outright obstruction of the tools and programs we need to solve the problem.

But President Obama remains committed to making the United States the global leader in the fight against climate change—and so do I. In Paris this week, world leaders have the best chance in years to forge a new, durable, ambitious international climate agreement. I believe they must be guided by three principles. First, all countries must take responsibility for combating this global crisis, and put forward commitments to curb their own greenhouse gas emissions. Second, the agreement should galvanize financial assistance for, and spur private investment in, developing countries to help them adapt and achieve sustainable economic growth.

And finally, it must be an agreement that can be strengthened over time. Countries should agree to come together regularly to raise their collective ambition. In the years ahead, technology will improve and become even cheaper; more companies and investors will put skin in the game; and city and state leaders will take actions that outstrip the ambitions of their capitals. Solving the climate challenge for the long term will take more than the solutions we have in 2015—it will require the new tools we build together.

In Copenhagen in 2009, President Obama and I had to burst into a secret meeting of leaders from China, India, Brazil, and South Africa to break a deadlock and deliver the first international climate agreement in which all major economies, not just the developed world, pledged to take action.

We’ve come so far since then. Over the past year, 164 countries accounting for 90 percent of global emissions have announced national targets and measures to reduce pollution that they are ready to codify in Paris, recognizing that cutting emissions and investing in clean energy isn’t just good for the planet—it’s good economic sense. The United States and China led the way with ambitious goals to cut carbon pollution and deploy more clean energy, and have already begun taking action to achieve them.

Still, getting the job done in Paris will require skillful diplomacy and robust American leadership — I know that from personal experience. As Secretary of State, I put combating climate change on the agenda for my first trip to Beijing and kept it there over the next four years. I appointed the first high-level special envoy for climate change and led an international effort to launch the Climate and Clean Air Coalition to reduce so-called “super pollutants” that make up just a fraction of emissions, but drive a disproportionate share of warming.

As President, I will protect and build on the progress President Obama has made at home. I will set ambitious goals—to see 500 million solar panels installed within four years and enough renewable electricity to power every home in America within 10 years. I’ll also pursue a new North American Climate Compact, because the United States, Canada and Mexico should work together to build a clean energy future for our continent.

And the Republican deniers, defeatists and obstructionists should know—their cynical efforts will fail. Not only are they on the wrong side of science and of history, they are increasingly on the wrong side of their own voters, as a majority of Republicans accept the science of climate change, and support solutions like clean energy.

We must reject the false choice between combating climate change and fostering strong economic growth. If any country can prove that, it’s the United States. Under President Obama, we’re leading the world in the fight against climate change. I won’t let anyone to take us backward, deny our economy the benefits of harnessing a clean energy future, or force our children to endure the catastrophe that would result from unchecked climate change.

Once again, the world looks to Paris—this time in hope. Global challenges demand global solutions. The fight against climate change will be long. It will take the efforts of every country, every industry, and every community. It will take the leadership of every President. But at last—in Paris—the framework of a lasting solution is within reach. We must seize this moment.

Hillary Clinton is a Democratic candidate for president.

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