280857 Carbon dioxide sometimes harms people. CK 266244 Trees give off oxygen and absorb carbon dioxide. CK 280858 The amount of carbon dioxide has increased by 10 percent. CM 322438 Massive amounts of carbon dioxide are generated every day. CM 282138 Tropical rainforests produce oxygen and consume carbon dioxide. papabear 681001 Forests regulate the water cycle and take away harmful carbon dioxide. Source_VOA 277154 It is said that global warming is directly related to carbon dioxide emissions. CK 1141316 A carbon footprint is the amount of carbon dioxide pollution that we produce as a result of our activities. Some people try to reduce their carbon footprint because they are concerned about climate change. Source_VOA