Until the late 80s, fashion retailers and brands would typically have two main collections a year: spring/summer and autumn/winter. Then, in the 90s things changed dramatically. Increased competition saw retailers incentivising customers to visit their stores more frequently. To do this they expanded their product ranges. The latest fashions seen on runways and celebrities began to rapidly populate high-street retailers' ranges. Designers and trend seekers would turn a garment around from drawing to shop floor in just two weeks. The era of "super cheap and super fast" took off.

Ever since, collections have become increasingly fragmented with three to five mid-season flashes in addition to the two main collections, and, in some extreme cases, there can be as many as eighteen collections a year. 'Here today, gone tomorrow' has become the norm.

Fashion retailers have changed how and where they buy

This new "fast fashion" model has considerably changed the role of fashion retailers in their supply-chains, specifically how and where they buy.

In the past, lead times typically used to be between 90 and 120 days. These have come down to between 45 and 30 days, or even less. As a management briefing from Just Style in 2006 pointed out, instead of 40,000 garments being manufactured across four styles for 20 weeks at a rate of 500 per styles per week, now only the first five weeks are contractually confirmed (usually at four styles at 500 per style per week). This is equivalent to a total commitment of 10,000 garments. What happens to the remaining estimated 30,000 that will be needed? Their fate remains undecided until the first batch is already on sale in store.

The end of the 1974 Multi Fibre Agreement (MFA) in 2005, triggered a shift in market shares of garments from developing countries. Today, almost three quarters of world clothing exports are produced in developing countries with the top three exporters being Asia (54%), South America (14%) and Africa (6%). More than a quarter of the world's production of clothing and textiles now happens in China, nearly double its pre-2005 market share.

How has the role of fashion retailers changed?

Over the course of decades, large fashion retailers have acquired significant power as they are in direct contact with the end customer and can therefore influence preference. Retailers are also at the root of globalisation of consumers' tastes. Wherever one goes, people dress very similarly. Global retailers only minimally adapt what they sell in Moscow and London, Tokyo or Buenos Aires.

The growing complexity of the supply chains and functions of large fashion retail chains has also meant that a company's activity is not restricted to the core business of retail distribution. As a result supply chains have become largely opague and nearly impossibly to track.

Higher pressure on suppliers to the fashion industry

Buyers today are substantially larger in size than the suppliers they source from, and hence clearly hold the bargaining as well as the market power. And with shorter lead and process times, the pressure on suppliers to cut costs, if not corners, has increased.

In Bangladesh, where 80% of the economy depends on the fashion industry, the minimum wage in 2006 was £7.16 a month. Taking into consideration inflation and subsequent real wage levels, that is two and a half times less than the £18 it was worth in 1994 when it was legislated. Meanwhile the price of essential commodities like rice, sugar, cooking oil and water have risen by 200%, making it virtually impossible for workers to support their families. Further, it is estimated that in cases where production is out sourced to a developing world country, workers' wages only account for between 0.5- 4% of the final retail cost of a garment.

Higher quantities and lower retail prices

Clothing is now cheaper than at any time in history. In the US, prices fell by 8.5% in the 1997-2010 period but prices of all other products rose by 57.3% in the same period. Expenditure on clothing increased (+300%) but the share of disposable income decreased dramatically. In 2009 Americans bought $326 billion worth of clothing using as little as 2.98% of their income, down from 4.78% in 1988 and 9% in 1950.

In the UK, between 2003 and 2007 garment prices fell by an average of 10% and, in 2006, people bought a third more clothes than in 2002.

As a direct consequence, textile production has doubled over the last thirty years. In 1977 the total demand amounted to thirty one million tonnes of fibre. In 2007, this figure had risen to nearly eight million tonnes.

Prices are lower and quality has decreased too

Cheap fashion uses cheap fibres, such as polyester and cotton. While polyester is an oil-based commodity, cotton on the other hand is not exactly the "good" crop it is usually perceived as. Cotton alone uses an estimated 22.5% of the world's insecticides and 10% of all pesticides many of which cause collateral damage in humans.Unsurprisingly, quicker production lowers product quality, and bad quality garments are easier to discard. It is estimated that more than 1 million tonnes of textiles are thrown away every year in the UK alone.

Is sustainability in today's fashion industry possible?

Twenty years ago sustainability was not on the agenda of the fashion industry's players. Today, sustainability forms part of their agenda, even though the degree of commitment of the different players varies considerably.

Many bright initiatives are led by independent fashion entrepreneurs that are seriously driven by their ethical objectives and are trying to find solutions to integrate sustainability into their business. Interesting initiatives from bigger brands are harder to come by, but they do exist: Marks & Spencer, Patagonia, Levi and Nike are examples.

Most initiatives that involve global brands have launched in the last 10 years. For example, The Ethical Trading Initiative (ETI) was launched in 1998 but really only gained momentum from 2000, and Made BY and the Ethical Fashion Forum were both launched in 2004.

Today there are more than one hundred different labels addressing consumers' health and environmental and social sustainability. But the key question is – will all of these efforts taken together really make a difference?

Ultimately, the drive has to come from the industry itself. While fashion companies still don't see sustainability as an integral part of their core business, change will be slow and difficult.

For Rio 2012, there is really only one topic on the agenda for the fashion industry; how can they make their supply chains measurably more transparent? Once full-scale transparency is in place the resulting evidence will be too compelling to ignore.