Two degrees Celsius is the magic number, the catastrophic, irreversible temperature shift that scientists warn could change the world in unending and devastating ways. The world is halfway to that mark, and it is with this simple fact in the background that the Paris Climate Summit took place. Weather disasters have increased in severity, and estimates of future tolls are terrifying. The World Health Organization has estimated that climate change causes 141,000 deaths annually, and that figure could rise to 250,000 by 2050. Meanwhile, the World Bank has projected that global warming will place 100 million people in extreme poverty by 2030. These possibilities, along with the millions of people displaced by climate change, was enough to push the world’s nations into a climate accord.

While occasionally effective, the United Nations doesn’t always have the best record of getting things done. There may have been a summit, but what will this summit yield, if anything? At the very least, it has brought the conversation to a table shared by nearly all the world’s nations. Indeed, the movement to fight climate change will have to be global, as developed nations worsen the problems and developing countries pose new and increasing threats to environments across the world.

Past meetings on climate change have taken place, most notably in Kyoto with the formation of the Kyoto Protocol, a set of standards and rules that tried to curb the speed of global change. Without U.S. support, however, the protocol lost a significant amount of ability to be effective.

But since 2007, China has been the world’s leading pollution creator — and nearly 1.3 million Chinese die annually from illness brought on by pollution. And on Dec. 8, Beijing was brought to a standstill after the government issued a red alert for pollution, with dense smog clouding the air. On that day, the air-quality index in Beijing was more than 10 times greater than the recommended healthy level set by the WHO. Still, the economic and political weight of China and the United States working in tandem could make significant progress in the future, if both are willing to play by rules and think long term.

Of course, U.S. reluctance to change isn’t surprising; 25 percent of Americans still don’t believe there is significant evidence of climate change. Fortunately, the Paris accord has set up guidelines and structures that should force all nations to re-evaluate their carbon emissions, even if they’d rather not.

“The Paris agreement establishes the enduring framework the world needs to solve the climate crisis,” President Obama said. “It creates the mechanism, the architecture, for us to continually tackle this problem in an effective way.”

In the coming months, individual nations must ratify the agreements in Paris. The United States must make this swift and follow up on the promises if we want to be leaders on the global stage. Across the globe, nations must act quickly, as the agreement means nothing without action.

The ratification of the agreements will only happen in force if 55 nations agree to it — 196 parties were present at the summit. Those 55 nations must account for 55 percent of carbon emissions as well, meaning an abstention by China or the United State could be enough to end the lofty goals of global safety in Paris.

Though the agreement is a good start, the Daily Iowan Editorial Board believes there is far more to be done. The Paris agreement lacks in specificity on how to actually curb carbon emissions and fails to address what happens if countries affected in extreme ways by global warming (such as island nations) will be owed recompense.

Still, the Paris agreement is a step in the right direction. Now is the time to define U.S. leadership in the fight against climate change. With so many nations, businesses, and industries acknowledging the importance of this issue, the United States has the potential to reassert itself over China and Russia as the pre-eminent global leader under the banner of climate change.