One man's "massive rehabilitation" is another man's "massive pollution". Who's to say that deserts need rehabilitation, while grasslands don't? 4200 before present is no more the prefect climate date for Hunshandake than 1978 is for Minnesota. If you look at the geologic record, we should be "rehabilitating" Minnesota so that it has a mile thick ice cover, since that's been it's dominant climate over the past million years, or so.
Whatever is useful for humans is rehabilitation. :’) I think the main reason for the results of this study is to keep the Chicoms from trying to refoliate a marginal area.