Sustainability – The ability to continue indefinitely.
The fundamental issue is increasing the maximum sustainable population. What is the maximum number of people, living an acceptable quality of life, which the planet can sustain? Currently (with this definition of max sustainable population), that number is approximately zero due to our reliance on non-renewable resources, such as oil. With current habits, technology, and demand, oil will be depleted (before significant effects of global warming) and the quality of life would be decimated with a halted economy. It may be that electric cars will become available to the mass market, and when that time arrives, most electricity needs to come from renewable resources (solar, wind, fusion, etc) or else their purpose is largely void. While electric vehicles and bio-diesel frieght carriers and heavy equipment will be a great step toward sustainable humanity, there are other very important civilizational issues directly related to increasing the maximum sustainable population.
The infrastructure required for personal transport (cars) inherently leads to sprawl because it is easier to handle automobiles with more space. This consumes land much needed for agriculture to feed a maximizing population – as well as encroaching upon sensitive ecosystems. As the population increases, so would our consumption of land for sprawling development (with current habits). When infrastructure is strung out to pave, power, and service homes and businesses sprawled out on the land, more funding is necessary for the maintenance of the expansive web of infrastructure (the tax burden per individual for this maintenance would be, and already is, unacceptably economically draining). Therefore, electric cars and sustainable electricity generation are not all that must happen to truly maximize the maximum sustainable population.
We must densify. Densification allows for walkable towns and cities, and makes mass transit feasible. The average person should be able to walk, bike, or utilize mass transit systems to reach their daily needs such as work, school, groceries, etc. This average person should not require a personal automobile. The benefits of walkable urban design extend beyond conservation of land, and less costly infrastructure. Providing the option to walk to your daily needs would lead to a healthier population, thus reducing the burdensome costs of healthcare. Also, contrary to common perception, most dense areas (5 residential units per acre or more) experience less crime because of the “eyes on the street” phenomenon in which the density of people itself deters criminal activity (isolated/low density areas in cities are where most crimes occur). Architecture and urban planning must be understood, by both design professionals and the general public, as the most significant factors in the sustainability of society.
It is imperative that densification, and development of a sustainable energy infrastructure happens before current habits plunder our economy and force a very painful societal awakening. Smart densification and sustainable energy generation are the most important steps toward achieving sustainable prosperity.