The world's population is growing by 1,000 million a decade at current rates. This is putting tremendous stress on global resources such as agricultural land, which itself is increasingly needed to feed the rapidly growing global population. A relatively small proportion, or about 22% of Earth's total land area is potentially arable. Yet, every year an estimated 6-7 million hectares of agricultural land is made unproductive because of erosion, 1.5 million hectares is affected by reduced productivity because of waterlogging, salinization and alkalinization, and almost 1 million hectares, much of it prime land in rain-fed areas, is being lost to urbanization. Since agricultural land continues to be lost, it is widely agreed that at the very least the most productive or fertile agricultural land should be protected.