The world is divided politically. But ecologically it is tightly interwoven. There are no useless threads in the fabric of the ecosystem. If you cut any one of them you will unravel many others. We've uncovered other worlds with choking atmospheres and deadly surfaces. Shall we then recreate these hells on earth? We've encountered desolate moons and barren asteroids. Shall we then scar and crater this blue-green world in their likeness? Natural catastrophes are rare. But they come often enough. We need not force the hand of nature. If we ruin the earth, there is no place else to go. This is not a disposable world. And we are not yet able to re-engineer other planets. The cruelest desert on earth is far more hospitable than any place on mars.