Sustainability - the definiton

So what is sustainability? I feel I have started off my research without actually exploring the basics.
The New Zealand Ministry of The Environment sums up, "Sustainability is often perceived as a complex concept to understand and it can be hard for businesses to discover the benefits it offers. In essence, sustainability is about meeting the needs of today, without adversely impacting on the needs of tomorrow. As a term it can be applied across a range of areas, such as the environment, the society and the economy."
But what is sustainable fashion? The phrase is thrown around so freely, but yet it is not commonly defined. I want to pin down exactly what the label encompasses. A simple google of 'definition of sustainable fashion', doesn't seem to quite cut it as I quickly found out.

At a Copenhagen conference, a collection of designers were asked what their definition of sustainability was:

Frida Giannini, of Gucci - "Quality items that stand the test of time ... a timeless handbag that you wear again and again, and can pass on"

Oscar de la Renta - "A commitment to the traditional techniques, and not just the art, of making clothes. I work today in the same way that I first learnt in the ateliers of Balenciaga and Lanvin 50 years ago ... clothes that are not only beautiful but extremely well made"

Anya Hindmarch (I'm not a plastic bag) - "Locally sourced materials that don't pollute in their creation or demise (preferably recycled) and with limited transportation to achieve the completed product."

Dries van Noten - "Sustainable fashion is a contradiction in terms. It refers to how the fabric used for a new garment has been produced ... I believe, we need to consider this issue from a more macro and profound perspective. Though a cotton may be unbleached, we need to examine how it arrives to the manufacturer or to us the wearer. What was the 'carbon imprint' of its delivery, for example?"

All a very mixed understanding (or distinct lack of understanding what so ever!) but this range illustrates the blur when it come to sustainability.

Kate Fletcher demonstrates a deeper understanding, "Fashion that fosters ecological integrity and social quality through products, practices of use and relationships. Fashion that helps us engage, connect and better understand ourselves, each other and our world".

To me sustainable fashion is an ever evolving movement, which in turn has an ever evolving definition. Sustainability is a future thinking process, a way of bridging the gap between humanity and the environment, working together harmoniously through 'green' ways. Whether it be through material choices, labour choices, manufacturing choices, design choices, zero waste, they all have elements of sustainable thinking. I am still having difficulties with defining how much of these things a garment or design has to have to gain the label of being sustainable, it seems anyone can call themselves 'green' or 'eco-friendly', but what is the reality of this? it can be recyled? so can milk bottles! I want to explore all the sustainable fashion elements and how they in turn are 'sustaining' our world and work out how I can incorporate these into my design work.