After two weeks of meetings in Paris, 195 countries reached an agreement on December 12 to do with climate  change. It's the first time in history that most of the world's countries, rich or poor, agreed to take action. The agreement sets the long-time goal of making sure the world temperature does not get 2degC higher than the levels in the 1800s. Otherwise there will be serious problems on Earth like natural disasters. The agreement also asks countries to volunteer to make promises based on each country's economy , politics and technology. For developed countries, they will do even more. They have a plan to offer over $100 billion (about 647 billion yuan) to help poorer countries develop clean energy like water and wind power. Besides, there are some legally binding   rules. Those countries need to set national goals for cutting greenhouse gas emissions   every five years. And they will publicly report their progress every five years starting in 2023. However, the Paris Agreement alone won't solve the climate change problem. The future depends on how well each country will carry out their promises. The agreement reached by 195 countries is about the  _  .
world economy gas emissions climate change natural disasters