Biologist Prof Philip Fearnside talks to Sky News' Mark Austin in the Amazon rainforest about what the trees there do for the planet, and where we may end up if they are cut down.

He talked about a future where the Amazon could be turned into a savanna which would leave climate change 'out of control'.

SUBSCRIBE to our YouTube channel for more videos: http://www.youtube.com/skynews

Follow us on Twitter: https://twitter.com/skynews

Like us on Facebook: https://www.facebook.com/skynews

Follow us on Instagram: https://www.instagram.com/skynews

For more content go to http://news.sky.com and download our apps:

Apple: https://itunes.apple.com/gb/app/sky-news/id316391924?mt=8

Android https://play.google.com/store/apps/details?id=com.bskyb.skynews.android&hl=en_GB

Sky News videos are now available in Spanish here/Los video de Sky News están disponibles en español aquí https://www.youtube.com/channel/UCzG5BnqHO8oNlrPDW9CYJog