Wind turbine

Limits of Life Cycle Assessment

Using the LCA approach can give useful information but it does have its limitations.

Comparing different factors

What is more important: the use of water resources or Carbon dioxide emissions?

How do you compare the effects of global warming with people's need for clean drinking water?

Different factors can be given a 'weighting value' to allow them to be compared. However, these are based on opinions and different priorities.

Drawing the boundaries

Looking at a life cycle can be extremely complex. It is difficult to see where the assessment should stop.

Think about the production of a wooden pencil. This would seem to be fairly simple. But should the sawmill be included? And what about the truck that transports the wood? What materials are needed to make the truck?

The questions can go on and on if a boundary is not drawn around the process.

Social and Economic sustainability

Environmental impacts are carefully measured but social and economic factors are much harder to include in the life cycle.

Woodland

Renewable and non-renewable resources

Using resources such as oil and gas for plastics must be looked at alongside the use of resources such as wood.

Some hardwood forests are being cut down and these will not grow back for hundreds of years. How does this compare to the use of fossil fuels?

Smoking chimney

Wastes

Which is the most harmful: burning wastes which releases emissions to air or using landfill sites? Judgments need to be made during the life cycle analysis.

Recycling

Recycle logo

Some materials, such as aluminium, paper and PVC can be recycled. This will clearly influence their life cycle. Should this be included in the analysis, even though it depends on people recycling their wastes?

Recycling also depends on the facilities available. For example, transporting renewable materials over long distances could produce more carbon dioxide from the transport than is saved by recycling. Economically this may be too expensive.