World leaders, who have been gathering in the French capital of Paris to discuss how to tackle climate change, have agreed on a plan.
Nearly 200 countries have made a pact to attempt to limit the temperature on the earth from rising too quickly and too high.
American President Barack Obama has said the landmark deal was "not perfect" but offers "the best chance we have" to save the planet.
China's chief negotiator Xie Zhenhua also said the deal was not perfect. But he added that "this does not prevent us from marching historical steps forward".
The things they agreed on included:
• To reduce the amount of harmful greenhouse gas produced and increase renewable types of energy like wind, solar and wave power
• To keep global temperature increase "well below" 2C (3.6F) and to try to limit it to 1.5C
• To review progress every five years
• To spend $100 billion dollars a year in climate finance for poorer countries by 2020, with a commitment to further finance in the future.