A natural rainforest emits and absorbs vast quantities of carbon dioxide. On a global scale, they may have other climatic effects (on cloud formation, for example, by recycling water vapour).No rainforest today can be considered to be undisturbed.
Many foods originally came from tropical forests, and are still mostly grown on plantations in regions that were formerly primary forest. Also, plant derived medicines are commonly used for fever, fungal infections, burns, gastrointestinal problems, pain, respiratory problems, and wound treatment.