If 30% is literally the bare minimum required to avoid environmental collapse, it's obviously not enough. That leaves no leeway, no room for error or accidents, man-made or natural, even IF everyone actually abides by it. It's pure human hubris to also assume these calculations are 100% accurate when dealing with such complex systems or that some new factors couldn't change things. You don't park a car on the very edge of a cliff and then get to be shocked that something happened to it when you could have easily parked it at a safer distance.