CNN News:50名各国领袖出席巴黎气候峰会 特朗普缺席不来

An international summit has begun in the French capital. It involves more than 50 leaders from around the world and its focus is on climate change.
Two years ago, Paris hosted an event called COP21, meaning Conference of Parties 21. It brought together negotiators from 195 countries and it had the goal of reducing carbon emissions, where greenhouse gas emissions.
Most climate scientists say these emissions which are caused by human activity are contributing to rising global temperatures. And some critics say the climate changes naturally and that the earth can adjust to it. In the 2015 summit, an agreement was reached. The countries would set their own goals for reducing their emissions. It wasn't binding, meaning countries didn't actually have to fulfill their commitments.

But U.S. President Barack Obama, who was in office at that time, said the Paris agreement established a framework to address climate change and called it the best chance to save the planet. Not everyone agreed, but all except two countries signed on to the deal and the two holdouts joined later.
But earlier this year, the U.S. said it would withdraw. Newly inaugurated President Donald Trump said the Paris agreement disadvantage the U.S. and would cause millions of jobs. He added that America would push for a new agreement that was more fair.
Still, the other countries stayed in. And two years to the day after the initial deal was made, a new summit kicked off in Paris with the goal of jumpstarting a transition that's been lagging.