Does business have a duty to promote sustainable consumption?

No, and then again perhaps maybe.

Why would I, a diehard liberal tree hugging eco-vegetarian, say that business does not have a duty to promote sustainable consumption?

Thats promote, and not produce sustainably.

Business, (keeping strictly to capitalist economies) is formed to earn profit that will increase the wealth of its owners (and, arguably, its employees and society as a whole) and to grow the business to generate more wealth and so on. It does this by providing goods and services to consumers.

Michealis puts an interesting Darwinian spin on it by pointing out that the rules of business are reinforced by the survival of the fittest companies and the failures of the unfit. So, rather like money itself, business has no morality no soul or ethical responsibilities other than the generation of wealth through the production of things that can be consumed. If a business cannot do this it will become extinct.

But business does not exist in a vacuum. It exists within a society, and, as pointed out in the Story of Stuff, there are consumers who demand products and services and there are the democratically elected representatives of these consumers. It is the role of government to place society’s morality upon business and to institute laws and regulations accordingly to shape and influence how business goes about its business.

So business will not promote sustainable consumption unless it makes sense and its survival depends upon it, i.e. Until consumers demand it and governments reflect this in the laws and regulations it institutes.

But there is a problem with this, again raised by both Leonard and the glorious Adam Smith in the Wealth of Nations(1776):
To found a great empire for the sole purpose of raising up a people of customers may at first sight appear a project fit only for a nation of shopkeepers. It is, however, a project altogether unfit for a nation of shopkeepers; but extremely fit for a nation whose government is influenced by shopkeepers.

Sometimes governments forget who they represent, and that’s when, socially, things can get interesting. But thats a different topic.