Ecological doom-loops: Why ecosystem collapses may occur much sooner than expected

Around the world, rainforests are becoming savanna or farmland, savanna is drying out and turning into desert, and icy tundra is thawing. Indeed, scientific studies have now recorded "regime shifts" like these in more than 20 different types of ecosystem where tipping points have been passed. Around the world, more than 20% of ecosystems are in danger of shifting or collapsing into something different.