Johan Rockström

"We see evidence that lakes and forests and wetlands can have different equilibria — so you have a savanna system that may be stable and thriving, but it can also tip over and become an arid steppe if pushed too far by warming, land degradation and biodiversity loss. A clear-water lake can become a murky, biodiversity-low anoxic lake. Unfortunately, the science is increasingly showing that even large systems can tip."

"We are on average, moving towards four degrees warming this century. And we haven’t been in a four-degree warmer world for the past four million years. So it’s not as if it’s a place we know very well."

"Meat plays a disproportionately large role in causing this overuse of freshwater. Twenty-five percent of the rivers in the world no longer reach the ocean, because we're taking out so much water to produce animal feed. … Agriculture is not only the biggest culprit threatening the future for humanity on Earth, it is also the biggest and most important silver bullet to a solution."