香蕉视频

Professor Don Smith, chair of McGill鈥檚 Department of Plant Science and scientific director of the Green Crop Network, is not a man to mince words. 鈥淭here is a time when we are going to have to ask ourselves, 鈥業s the planet capable of supporting six billion people? That time is right now.鈥欌��

Humans are consuming food and fuel in ever-increasing quantities and, as the world turns to plant sources to find non-fossil energy sources, more and more of the elements necessary to support plant life are disappearing. 鈥淭he world is running out of phosphorus at an alarming rate,鈥� notes Smith, 鈥渁nd we need phosphorus to grow crops.鈥� It鈥檚 not just phosphorus, either: water, energy and micronutrients such as copper and zinc鈥攁ll are crucial to agriculture, all are increasingly scarce.

Biofuels were once thought of as a can鈥檛-miss replacement for oil and other non-renewable energy sources. But many types of biofuels, such as those produced from palm oil in Indonesia, divert potential food materials away from the food stream. The grain required to fill a large car鈥檚 gas tank with ethanol, for example, could feed one per son for a year. In short, if a harvest is feeding engines, it鈥檚 not feeding people. How should the world鈥檚 limited growing resources be used, then? Food or fuel? Factoring in global warming鈥攁lthough many trees and plants 鈥渆at鈥� carbon dioxide, the production of some biofuels can actually increase the load of greenhouse gases鈥攐nly further complicates the matter.