From New Scientist comes this article on How nature is reclaiming farmland:
IT’S AN odd juxtaposition that’s starting to pop up in far-flung places around the world. Across the hilly regions of China, the scars of agriculture are being covered by a messy mix of trees and shrubs. In parts of Iran, Australia and Kazakhstan, wild animals are reclaiming swathes of abandoned pasture. And in Portugal, Chile and Argentina, abandoned farms serve as lifelines that connect fragments of intact wilderness.
The landscapes are different but all are evidence of a startling new trend. For the first time on record, the world’s farmland is shrinking. Every two years, an area roughly the size of the UK is abandoned. Has humanity’s insatiable land grab hit a turning point? And can we use this opportunity to build a world where farming has a smaller footprint, and nature gets a chance to rebound from the huge toll we have inflicted upon it?
For most of the 20th century, agriculture constantly spread out. By the 1990s, farms occupied 38 per cent of the world’s land. The impact on ecosystems is well documented: 27 per cent of tropical forests and 45 per cent of temperate forests were cleared in the process.
With slowing birth rates and rising productivity on good farm land, some countries are taking a page from the United States and taking very marginal low-production lands out of production or aggressively tree-planting to slow erosion and increase more appropriate agricultural production.