Christopher Mims in Mother Board:
If you think of the Earth as a space ship with an energy budget that equals the input of the sun, which is exactly what it is, then you can imagine that there is a total quantity of biological productivity of which our planet is capable. Estimates say that humans are already appropriating between one quarter and one half of this productivity. The total amount of land given to crops is tied with forests as the single largest terrestrial ecosystem. Our food production requires almost a quarter of the total land area of the planet.
We have basically killed most of the wildlife that was available to us only a single generation ago. Chief scientist of the Nature Conservancy Peter Kareiva has declared that while 13 percent of Earth’s landmass is now protected as some sort of park — an area larger than all of South America — we have completely failed to stop the eradication of the plant and animal inhabitants of these “wild” places. Much of this is due to the fact that wild things are apparently quite tasty. And if you think this is limited to the land, the evidence is that our oceans are in even worse shape, with global fishing stocks set to collapse by mid-century. Meanwhile, as we all know, climate change is only accelerating what scientists now call the “sixth extinction.” Or in other words, the sixth time in the 4 billion year history of life on earth that the entire planet was so challenged that a vast majority of life came perilously close to being snuffed out.