[Editor's Note: John Anderson, president and CEO of Levi Strauss & Co., provided the following excerpt of a speech he recently delivered at the Haas School of Business of the University of California at Berkeley.]

To me, sustainability has become the touchstone of the entire discussion about the relationship between business and the society it serves.

It is a global issue, with an impact in every country, and every community.

At Levi Strauss & Co., thinking about sustainability was just a natural extension of the way we saw ourselves and our responsibility. By the later part of the last century, we had become one of the world's most famous global brands. We had factories around the world. Hundreds of stores. We shipped and trucked our clothes hundreds of thousands of miles. We made an impact on the environment that we were very much aware of.

And we tried to do something about it. For more than two decades, Levi's has been a leader on environmental issues. Two decades ago we established our own global sourcing guidelines that stated, among other things, that we would only do business with partners who share our commitment to the environment and conduct their business in line with our philosophy.

And we kept pushing, with a restricted substance list, global effluent guidelines, and ambitious recycling and reuse programs. The long-term goal remains to be a zero-impact company. We want to build sustainability into everything we do so that our profitable growth helps restore the environment.

So we decided to take another step. We wanted to build a rigorous and credible assessment of our own impact on sustainability. Something that was science-based and led by a independent third-party. We wanted to understand not just the programs we had started, but the real impact of our products in their entire lifecycle.

We started with the basics. One pair of Levi's 501 Jeans. One pair of Dockers Original Khakis.

Our study found that a single pair of 501s, from growing the cotton to consumer care and disposal really does have an impact. A significant one. The lifecycle study of one pair of 501s generates 32.3 kilograms of carbon (78 miles of driving), 3480 liters of water (53 showers) and 400 megajoules of energy (running a plasma tv for 318 hours).

But the real lesson of the lifecycle study is that some of the biggest sustainability impacts have nothing to do with processing denim, sewing jeans or shipping clothes.