The concept is usually referenced to the work of Jesse Ausubel and Iddo Wernick.[1][8][9] They predict that over the next fifty years an area of at least 146 million hectares is going to be released from farming and will probably revert to its natural state.[9] As land conversion (from a natural state to human use) is one of the greatest threats to the natural environment in general, and biodiversity in particular, this is seen as good for the environment.[10]