Johan Rockström

"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."

"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."

"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 were 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."