Before we can run we must learn to walk. Or put another way, before we can fly we must learn to swim. If we are ever to advance beyond our one-planet limitation, we must learn to live with pressure differentials and within closed eco-systems. We must learn to live without damaging our environment, and how to effectively utilize the abundant energy of renewable sources. We must also give ourselves time to develop the technologies and social institutions we will need for our eventual expansion into space.
To do so we need not look any further than our unexplored ocean environments. By utilizing floating and undersea colonies, not only do we increase the earth's carrying capacity by a few billion people--no sense limiting ourselves to land--we also permanently expand into an environment that humanity has only ever passed through. It is no small task to create large floating cities, but it is not beyond us. Not only is Aquarius possible with today's technology, it is economical from both the fiscal and environmental perspective.
The Heart of Aquarius
At the center of each ocean colony will be one, or several, Ocean Thermal Energy Converters (OTEC's). These converters utilize the solar energy trapped along the ocean surfaces, exploiting the temperature difference between the surface water and the ocean floor to drive massive turbines. Capable of sustaining a colony of many thousands of people, this use of renewable energy will mark a major milestone in the progress of humanity.
Abundance in Food
Nutrients, such as nitrogen, sink to the ocean floor. When they are brought back up to the surface by currents, an explosion of life occurs. These upwellings are the source of nearly 50% of the world's fish harvest. By drawing cold water up from the floor of the ocean, the OTEC's at the heart of Aquarius will pump out the lifeblood of the colony, giving rise to an abundance of farmable marine life. Another by-product flowing from the OTEC's is humanities greatest physical need: fresh water.
Advantages to the Rest of the World
An ocean colony will stir the curiosity of humanity, and hordes of tourists will flock to these areas to experience a stimulating and wonderfully new approach to life. Although the entertainment value of such colonies is notable, the most important global benefits are more tangible. With enough colonies utilizing OTEC's, the energy output of the world could easily double, all through the use of renewable, clean energy. A single colony with several OTEC's could create an upwelling over half the size of the Nile river, creating a massive source of exportable marine agriculture.
In addition to new sources of abundant energy and food, Aquarius colonies can reverse environmental destruction. Algae, which consists of 20% carbon, is but one step in the marine food chain. Instead of becoming fish food, the algae created by the OTEC upwelling can be captured and allowed to sink to the bottom of the ocean, carrying the carbon with it. We have the option of trading fish farms for carbon dioxide sponges. Regardless of our choice, cold water from the floor of the ocean will be pumped to the surface and released. This cooling effect will lower the evaporation rate of water vapour--a greenhouse gas many times more potent that carbon dioxide.
The growing discord in this world suggests a need for new economic systems. Currently no place exists to test one of the many proposed economic models, as no land-based community is suited for such a task. Aquarius colonies are unique in their isolation, and as such they are designed to be largely independent of surrounding human activity. By piloting new economic structures in these floating cities, humanity will gain valuable insights into social evolution.