One of the things that people point to is the idea of "off-setting" their carbon footprint. They pay for people to do things like plant trees or other things so that they feel that someone is taking enough carbon out of the atmosphere to off set the amount that they are putting in.
This is also a part of the carbon trading system where certain companies pay to offset their emissions. The problem is that there are huge amounts of faults in the system and there is also no real way of holding people accountable if they just take your money and don't plant trees, etc.
So I would say right now there are few things that one can do if they are in a situation where they absolutely cannot be sustainable. But Carbon Offsets are one possible option.
Non-sustainable business means a business that cannot expect to continue to do business and grow for long because of the environmental damage and other cost to the society caused by its manufacturing and other activities, and by the consumption and disposal of its products.
There are no clear criteria for qualifying a business as non-sustainable. For example, do we consider the business cigarette manufacturing business as non-sustainable because of the harm caused by smoking to the health of direct smokers as well as passive smokers?
Different types of businesses may be considered non-sustainable for many different reasons. Accordingly the the step they need to take to reduce their global foot print - that is, adverse impact of their activity on global environment - will also needs to be different. A company manufacturing newsprint paper is non-sustainable because the wood it uses for making the paper is reducing the forest cover. A company like this could undertake a tree plantation program to become sustainable. A power utility may be considered non-sustainable because of high environmental pollution created by its coal operated power plants. This company may have to improve its coal combustion and power generation technology, and introduce equipment to improve the quality of its exhaust. Such company may also benefit by adopting generating electricity from renewable sources of energy and nuclear energy. A petroleum company may find is advisable to go in for development of alternative bio fuels. Thus each business must decide appropriate method of reducing global footprint suitable for its business and its situation.