This Project speculates upon the green futures of 10,000 geographically real cities and towns throughout the world. This week, we showcase Karachi in the year 2121. Karachi -- nowadays the biggest city in Pakistan -- has severe problems with the silting-up of its harbor and waterways. Transportation, and the marine environment, are both so grossly degraded by silting that they are each being brought to the point of dysfunction. The silting is a natural process, the rivers b