In 200 years, the path we are currently on will undoubtedly include a large scale growth of urban environments, both in size and population density. Cities across the world will grow both upwards, with the construction of newer, taller buildings, and outwards, with the continuing forces of suburbanization and urban migration. However, Washington DC is in a very unique position. As an urban center, it is constrained both by height and area. No buildings in the city will ever be built higher than the Washington Monument (barring a revision of this norm, which I find extremely doubtful). In addition, the city limits are constrained by the borders of the District itself, so any commercial buildings wishing to add to the commerce of the city will soon run out of a very limited space.

This being said, I think that DC would undergo a large scale zoning reform, allowing more and more areas of the district to convert to commercial rather than residential. Meanwhile, the suburbs in surrounding Virginia and Maryland will continue to spread further and further away from the city, likely to be accompanied by increases in traffic congestion and air pollution.

This is the city we should expect if we dont make the necessary changes to combat our attack on our natural environment. The DC I would like to see in 200 years would be entirely dependent on local agriculture for its sustenance. I dont see the physical layout of the city changing much, especially because so much of the city's form and function pay homage to the founders of the country, monuments which are unlikely to be altered. However, the suburbs of the city will slowly transition into sustainable communities, and the farmland in Virginia will be utilized for the support of the people of DC. Energy sources, factories, and most other essential goods and services will be provided by the local community and the local resources available. Obviously, this setup will require a transformation in the expectations of American consumers. We can no longer expect fresh fruit in the middle of December, but we can instead find technological solutions to the constraints of our agricultural climate. These changes are absolutely imperative if we want to continue living in relative happiness for the next 200, if not 500, years.