The difference between the words green & sustainable

I really wanted to post this extract from an article online as it really helped me understand more about the word sustainable and tried to derive away from the word "green".

The idea of energy efficient, healthy buildings has been around for a long time, so why is it just now that the concept of “green” or “sustainable” building is entering the mainstream and catching the attention of fortune 500 companies like Wall Mart, Dupont, and Home Depot? There are probably several reasons; Global Warming, rising energy costs, the growing awareness and liability costs associated with “Sick Building Syndrome”, declining oil reserves, and concerns about our limited water supply. The list goes on, but whatever the reason or reasons, sustainable building is a concept whose time has come.

Which begs the question, what is IT? The ultimate definition depends on how one defines “green” as opposed to how one defines “sustainable”.

My personal definition of “green” is relatively simple. A home’s design is “green” if its serves to reduce many of the harmful impacts buildings have on our environment and our home’s inhabitants. So “green” home design revolves around four key issues:

1. Designing for energy efficiency including the use of renewal energy sources such as wind, geothermal, and solar.
2. Creating a healthy indoor air environment with adequate ventilation and making material choices that minimize volatile organic compound (VOC’s) out-gassing within the home.
3. Specifying building materials and resources that are sustainable, have low embodied energy, and produce a minimal amount of upstream environmental impact.
4. Providing for the efficient use of water via appliance, faucet, and shower head choices and in arid climates by xero-scaping and recycling grey water and capturing rain water for landscaping and other non-potable uses.

However, the words “green” and “sustainable” are often used interchangeably, and sustainable has a more precise meaning that is often obscured, distorted, and diluted by the commercialization and marketing of the green “movement”. In the context of our built environment sustainable takes its meaning from "sustainable agriculture", or “the ability…to produce food indefinitely, without causing irreversible damage to ecosystem health”. If we accept this as the basis for the definition sustainable building everything changes. For example, a 5,000 SF home with a HERS index of 70, bamboo floors, and Energy Star appliances may be “green”, but it is NOT sustainable. In the context of Global Warming and even the most optimistic projections of Peak Oil and Gas, only a home that meets zero energy standards can be considered sustainable.

Really helped me define my essay to be more precise and more fine. These words are connected but in a sense less broad and more precise. I really do think that with this considered, i can develop certain parts of my essay further