It's been called the world's lungs, the world's pharmacy and the world's air conditioner. It takes up only 6 percent of Earth's land, yet houses 50% of the world's species. Find out the math behind why they may be gone in 40 years in this episode.
Learn more about advertising on the HowStuffWorks podcasts at www.howstuffworks.com/advertisers.htm
And to learn about your ad choices when listening to podcasts, visit
https://www.howstuffworks.com/privacy.htm#ad-choices
